Private Water Supplies Sampling Procedures Manual
Version 3.0
July 2022
Table of Contents
Legislative background ........................................................................................ 1
UKAS Accreditation of certified sampling by ISO 17024 ........................................ 3
Health and safety ................................................................................................ 5
Investigational sampling ...................................................................................... 5
Document
control
................................................................................................ 5
Scope of Document ............................................................................................. 7
Changes and anomalies ....................................................................................... 7
Personal protective equipment (PPE) ................................................................... 8
Section 1 – Training and competency ..................................................................... 9
1.1
Competency................................................................................................... 9
1.2
Training ......................................................................................................... 9
1.1.1
Introduction .................................................................................................. 9
1.1.2
Induction ...................................................................................................... 9
Section 2 – Maintaining sample integrity ............................................................. 10
Section 3 – Sample
types
..................................................................................... 10
Section 4 – Bottle types ....................................................................................... 11
Section 5 – Preparation of chlorine solutions for tap disinfection ......................... 12
Section 6 – Order of sampling .............................................................................. 13
Section 7 – Sampling methods ............................................................................. 14
7.1
Initial checks ................................................................................................ 14
7.2
Plumbing metals (lead, copper, nickel) ........................................................ 14
7.3
Tap preparation………………………………………………………………………………………………15
7.4
Chemistry .................................................................................................... 15
7.41 Metals other than mercury and plumbing metals ....................................... 15
7.42 Pesticide samples ........................................................................................ 15
7.43 Trihalomethanes (THMS) samples ............................................................... 15
7.44 Polyaromatic hydrocarbons (PAH) samples ................................................. 16
7.45 Mercury and alpha and beta samples .......................................................... 16
7.46 Sulphide samples ......................................................................................... 16
7.47 General chemistry samples .......................................................................... 16
7.48 Radon sampling ........................................................................................... 16
7.49 Taste and odour sampling ............................................................................ 16
Section 8 – Microbiological sampling ................................................................... 16
Section 9 – Storage and transportation of samples…………………………………………………18
Appendices ......................................................................................................... 20
Appendix A ......................................................................................................... 20
A1. On site testing .............................................................................................. 20
A2. Procedure for temperature readings ............................................................. 20
A3. Chlorine residual measurements ................................................................... 21
A3.1 NN-Diethyl-p-phenylenediamine (DPD) reagents (DPD) .............................. 21
A4. Visual appearance ......................................................................................... 21
A5. Procedure for field odour test ....................................................................... 22
A6. Procedure for taste test (optional) ................................................................ 22
A7. Test equipment checks .................................................................................. 22
A8. Proformas ...................................................................................................... 22
Appendix B .......................................................................................................... 44
B.1
Procedure for sampling raw water from an open source ............................. 45
B.2
Procedure for lead stagnation sampling ...................................................... 46
1
Legislative background
This manual forms the basis of the BS EN ISO/IEC 17024 scheme BS EN ISO/IEC
17024:2012 Certification of Persons Scheme for sampling private water supplies. It
accords with both The Private Supplies (England) Regulations 2016, The Private
Water Supplies (England) (Amendment) Regulations 2018 and The Private Water
Supplies (Wales) Regulations 2017, hereafter referred to as the Regulations. It sets
out a common standard of sampling practice for monitoring private water supplies
by local authorities (or their contracted sampling service companies).
The Regulations require that local authorities in England and Wales monitor (sample
and analyse) private water supplies, when carrying out their duties under section 77
(1) of the Water industry Act 1991. It is however not mandatory for local authorities
to monitor supplies to single untenanted dwellings only unless they are requested
to do so by the dwelling owner or occupier.
Local authorities and any sampling company taking samples for regulatory purposes
must ensure that the regulatory requirements and standards are satisfied when
samples are taken. This includes the sample handling, transportation, and storage,
before analysis commences. This process must demonstrate compliance with the BS
EN ISO/IEC 17024 standard. To do so, a sampler accredited by the United Kingdom
Accreditation Service (UKAS) must check, from time to time, the local authority’s
compliance with these requirements.
The term “monitoring” refers to the taking of samples and their subsequent analysis
(testing) by a laboratory. Monitoring may be undertaken on an ad hoc basis or carried
out regularly to a defined frequency. Sampling is the act of filling bottles to a
prescribed method in the correct order for laboratory analysis. One sample may be
required for the testing of multiple parameters and therefore include different bottle
types. These must be taken in the correct order (see section 6).
The scope of this manual covers sampling procedures only. It does not cover laboratory
analytical methods. It should be noted however that private water supply samples
taken for regulatory purposes must be analysed in accordance with the BS EN ISO/IEC
17025 standard.
With regard sampling, the Regulations specify that the local authority ensures that:
▪ the sample is representative of the quality of the water at the time
of sampling.
▪ the person taking the sample is doing so in accordance with a system of
quality control to an appropriate standard.
▪ the sample is not contaminated in the course of being taken.
▪ the sample is kept at such a temperature and in such a condition as will
secure that there is no material alteration of the concentration or value for
2
the measurement or observation of which the sample is intended.
▪ the sample is analysed whether at the time and place it is taken or as soon
as reasonably practicable after it is taken – by or under supervision of a
person who is competent to perform that task.
3
UKAS Accreditation of certified sampling by BS EN ISO/IEC 17024
A sampler shall only be deemed competent when certified by a designated
certification body. The body shall be appointed by the scheme owner, namely The
Drinking Water Inspectorate. The sampling manual shall form the basis of the
scheme and shall be agreed by a committee of stakeholders.
The certification body shall be accredited by UKAS to demonstrate that it is
compliant with the ISO/IEC17024 standard. The model for this arrangement is
shown in Figure 1. The Certification Body is currently CATG, and the Scheme Owner
is currently The Drinking Water Inspectorate.
Figure 1 BS EN ISO/IEC 17024 model
Refer to BS EN ISO/IEC 17024:2012 Certification of Persons Scheme for sampling private water supplies in accordance with
the Private Water Supply Regulations
The procedures contained within this manual prescribe the standard sampling
arrangements and methods which local authorities and their contracted
representatives must follow for the purposes of regulatory monitoring of private
water supplies.
It should be noted that whilst procedures for the application of field-site testing
equipment and investigational sampling are covered in this manual for the
purpose of guidance, demonstration of competency in these areas is not a
requirement of the BS EN ISO/IEC 17024 scheme. This additional information is
included in Appendices for guidance only.
4
The word “sampler” is used in this manual as a generic term. It applies to any person
employed by a local authority or their contractor, for example a water sampling
company, trained under the BS EN ISO/IEC 17024 scheme, to collect water samples.
This includes, for example, Environmental Health Officers, Technical Officers and
persons contracted exclusively for sampling.
To differentiate between local manual adaptions, the standard manual within the
scheme shall be known as the “scheme manual”. The appendices of each local
manual must each contain the following with any local adaptations, where stated:
1. Sample bottles
It is recognised that bottle types may vary according to suppliers. Accordingly,
each sampler shall include within their version of the manual a
comprehensive photographic list of all bottle types used by the authority or
sampling company they are employed by. This must be appended to the
manual.
2. Sampling methods
Each sampler shall amend/replace any methods for the taking of samples in
section 8 of this manual, in accordance with its laboratory/supplier’s
instructions. All amendments and adaptations to a manual as per the above
requirements, and as defined in the scope of this document, shall be
incorporated into the manual.
3. Equipment
A list of all local sampling equipment shall be appended to the manual.
4. Authorisation to sample
A copy of, or a localised version of, the “Authorisation to carry out sampling”
proforma, which must provide the same information as that shown in the
scheme manual shall be appended to the manual.
5. Sample chain of custody form
A chain of custody form is a document that accompanies samples during their
transportation from the sampling location until they are signed over to the
laboratory. This is sometimes known as a laboratory submission form. A copy
of, or a localised version of the “Chain of Custody record” proforma, which
must provide the same information as that shown in the scheme manual shall
be appended to the manual.
5
6. Sample storage
A copy of, or a localised version of, the “Sample storage temperature record
and cleaning” proforma, which must provide the same information as that
shown in the scheme manual shall be appended to the manual.
7. Health and safety
Only the minimum health and safety requirements that are specific to certain
procedures have been included in the scheme manual. Samplers may incorporate
any additional local health and safety requirements in accordance with local policies
and procedures, as they see fit. Health and safety information is not part of the
accredited methodology but may be included in the local manual.
8
Investigational
sampling
Accredited methodology for the collection of investigational samples falls outside of
the scope of this scheme. However, by following the procedures in this manual a
sampler is following good sampling practice to a common standard.
Additional advice for sampling from other points for the purposes of undertaking
investigations, for example, at open water, can be found in Appendix B.
9 Document control
These procedures draw on the guidance on sampling best practice from The
Standing Committee of Analyst (SCA) Blue Book “The Microbiology of Drinking Water
(2010) – Part 2 - Practices and procedures for sampling”, available at Microsoft Word -
june22 (secureservercdn.net) This document forms part of a series of publications
detailing methods for the Examination of Waters and Associated materials.
The administration of this document and the methods and procedures contained
therein are maintained using a quality managed system. This is to ensure that the
All amendments and adaptations to a sampler’s manual as per the above
requirements, and as defined in the scope of this document shall be
incorporated into the manual prior to each prospective sampler’s
application for assessment and certification. This amended version of the
manual shall be presented to the certification body and assessed as part of
the applicant’s assessment. This shall be accompanied by a written
statement from the laboratory confirming that this complies with the
analytical method accredited under BS EN ISO/IEC 17025.
6
standard of sampling and on-site testing of private water supplies complies with the
Drinking Water Test Specification (DWTS). Each holder of the manual shall complete
the Version control record (Table 1).
7
Table 1: Version control record (internal use only)
Manual holder’s
name
Version
number of
manual
Date version
issued
Date manual
implemented
Date version
revoked
Scheme Manual and Local Manual Definition
• Scheme Manual – This refers to the latest version of this document
• Local Manual – a version of the current Scheme Manual that has additional
appendices describing sample bottles, sample methods, equipment, and other
forms where these differ from those described in the Scheme Manual
10 Scope of Document
This Scheme Manual covers the requirements for taking, transporting and storage of
samples for regulatory monitoring purposes.
In addition, this manual contains appendices which provide additional information
on best practice for other activities including for field testing and non-regulatory
sampling. The appendices do not form part of the scope for, or assessment of this
scheme, and are provided for guidance/best practice only.
11 Changes and anomalies
Users of this manual are encouraged to submit any suggested changes, or query any
aspect of the manual by the submission of a “Change request form” (See Appendix A8),
by email to the scheme owner for consideration of its inclusion, at each three yearly
review of the manual.
8
12 Personal protective equipment (PPE)
Eye protection, suitably protective gloves, and appropriate work-wear such as
coveralls, work trousers and long sleeved top need to be worn at all times when
mixing and applying the chlorine disinfectant solution. At NO time is bare skin to be
exposed to the chlorine disinfectant solution.
This PPE is in addition to any other PPE specified in local arrangements. All other
applicable local health and safety measures must be observed.
9
Section 1 – Training and competency
1.1
Competency
A sampler shall be deemed competent to take samples of private water supplies
when he/she has demonstrated compliance with the procedures laid down in this
manual to the satisfaction of the certification body named and designated in the
scheme. Those individuals deemed competent to sample by the certification body,
shall be awarded an authorised certificate. The certification body shall be accredited
by UKAS by demonstration of its compliance with BS EN ISO/IEC 17024. UKAS will
assess the certification body on an annual basis to determine ongoing compliance
with the BS EN ISO/IEC 17024 standard.
Ongoing local competency of samplers shall be demonstrated by the audit process
prescribed in the BS EN ISO/IEC 17024 scheme at the frequency specified.
Where ongoing competency of a sampler is not evident, the certification body will
suspend or withdraw that individual’s sampling certificate until their competency
can be demonstrated.
A local authority or sampling service company acting on behalf of a local authority
may suspend any sampler if malpractice is uncovered, according to their own
disciplinary procedures and when so doing, should inform the certifying body who will
decide if any sampling accreditation is withdrawn.
1.2
Training
1.1.1
Introduction
The training of samplers to meet the competency requirements of the scheme may
be carried out by the certification body, as described in BS EN ISO/IEC 17024 scheme
requirements or by an independent training provider. If training is delivered by a
certification body, then they must demonstrate independence between training and
examination.
1.1.2
Induction
Any managers responsible for samplers shall provide all certified samplers with the
tools, equipment, and personal protective equipment (PPE) required for sampling in
accordance with the procedures in this manual. A list of this equipment, including the
make, model and serial numbers of all test equipment shall be appended to the local
manual. This equipment shall include a current and numbered copy of the sampling
procedures manual that has been amended in accordance with the instructions 1-6
within the Scope of this manual. The designated technical manager must complete an
“Authorisation to carry out sampling record” (See Appendix A8) once he/she is
satisfied that the sampler has an BS EN ISO/IEC 17024 certificate of competency.
10
Section 2 – Maintaining sample integrity
Samples must remain refrigerated, including when they are in transit and being
stored. These must be transported in an upright within a temperature range of 2-8
°C in either a cool box or refrigerated unit on the vehicle. See section 9 for further
details. Samples should always be protected from direct sunlight as much as
possible.
Samplers shall always wear appropriate PPE to meet the relevant health and safety
risks at the time of sampling. Each sampling activity shall be subject to the
application of all health and safety requirements laid down by the local authority, or
sampler’s employer.
Never eat, smoke or drink whilst sampling. Hands should always be washed
between taking each set of samples.
All sample bottles must be appropriately labelled prior to sample collection to avoid
any bottles being misrepresented.
Section 3 – Sample types
Samples from private water supplies are taken for one of two reasons shown below:
(a)
Samples taken for the purposes of regulation 7 of the Regulations. These
must be taken at a tap that is representative of the supply, typically at the
point of consumption. If the water is used in food production, it must be
taken at the point at which it is used in the undertaking. If the water is
supplied from a tanker, at the point at which it emerges from the tanker.
The sample parameters, collection frequencies and points of collection are
prescribed by the Regulations.
(b)
Those samples taken for investigational purposes (regulation 16, or 18 in
Wales) – Investigational samples may be taken to help establish the cause
where it is suspected that a supply is unwholesome or there is a potential
danger to human health. They are also taken to verify that any remedial
action has been effective. Investigational samples are not within the scope
of the accreditation of this manual. However, sampling by the procedures
described in the scheme for and Appendix B for investigational purposes
should be followed for the purposes of standard good practice.
Sample types can also be designated according to the order in which they are
collected (pre-flush, post flush etc.). This sequence, the order of sampling, is an
essential element of sampling procedures. Figure 2 shows the order of sampling.
11
Section 4 – Bottle types
The analytical test requirements for any given sample will determine the bottle type.
Sample vessels (usually termed generically as bottles) vary in shape, size, volume,
and the material from which they are made from. This includes: the level of their
transparency, how they are pre-prepared (in some cases additives/preservatives are
added), whether they are reusable, and in their cap type and colour. The vessel used
must be of the appropriate type for the intended tests. The bottle type required for
a particular test or set of tests influences the method and sampling technique to be
applied.
A copy of the sampler’s analytical provider’s current bottle list must be appended to
the local manual and referenced where relevant in relation to its use.
Where relevant, each bottle shall be labelled with an expiry date (use-by) and if
necessary, with appropriate hazard labels, (this is added by the bottle provider
before it is issued for use). A designated Officer must assign specific individuals to
the responsibility of the management of sampling equipment, sample bottles and
their hygienic and secure storage. They should ensure any relevant health and safety
measures are applied. Bottles must be stored in a clean dry environment and locally
stored stocks must be managed such that out-of-date bottles are not used
accidentally. Any out-of-date sample bottles must be returned to the appropriate
bottle provider.
Where vessels have tamper-proof seals on the lids, these must be checked prior to
use to ensure they are undamaged. If they are damaged, they should be discarded
and returned to the provider.
Bottles used for the sampling and analysis of private water supplies must,
under the BS EN ISO/IEC 17024 scheme, only be those supplied by the
laboratory service provider. Analysis of samples must be carried out in
accordance with the Drinking Water Testing Specification and accredited to
BS EN ISO/IEC 17025 by UKAS.
12
Section 5 - Preparation of disinfectant for tap disinfection using a
sodium hypochlorite solution
Appropriate health and safety procedures need to be employed when using
hypochlorite (or chlorine) solutions. It is recommended that samplers undertake a
risk assessment for using these chemicals and reference the manufacturer’s hazard
and data sheets or COSSH sheets as part of the risk assessment. Even at low
concentrations chlorinated water can kill fish and cause environmental pollution, if
discharged to watercourses. It is therefore essential to plan how best to dispose of
chlorinated solutions to the environment. See below. (For example, diluted and
discharged to the foul sewer via a sink or toilet).
Commercial hypochlorite (sodium) solution is a caustic solution containing
between 10% and 15% available chlorine when new. Appropriate health
and safety measures should be put in place for its storage and handling.
“Rapid release” chlorine tablets are rapidly dissolving and when used in a known
volume of water, provide a simple and effective means of preparing chlorine
solutions of known strength, for disinfection purposes approved for use with
wholesome water. These are best used for making up small quantities of
solution.
The chlorine solution must be prepared to the concentration of 10,000 mg/L on the
day of sampling, prior to the sampling visit(s). This should be made to this
concentration using rapid release tablets or liquid sodium hypochlorite. When using
‘rapid release’ chlorine tablets it is necessary to consider the different types/sizes of
tablet available on the market, and the strength of solution that will be produced.
Refer to the manufacturer’s instructions/guidance notes. Pre-prepared proprietary
solutions should not be used. All local and manufacturers’ health and safety
precautions must be applied during the preparation of the solution.
The date, description and concentration of the solution must be clearly displayed on
the container together with any hazard labels. Instruction for preparation of this
solution must be included in the sampling procedures, including the
make/type/size/concentration of product used.
Any excess solution that is remaining after all sampling has been completed must be
suitably disposed of that day. These solutions cannot be allowed to enter watercourses
or surface water drains to comply with control of pollution environmental legislation.
Disposal of this must therefore be to a public foul sewer. This method of disposal is not
suitable for use where septic tanks or cesspits are in use. In these situations, tank
manufacturers’ instructions should be followed.
13
Section 6 – Order of sampling
Sampling in the correct order is an essential requirement of sampling methodology.
This ensures that samples are representative. The first bottle to be filled a sampling
sequence shall be determined by the analytical requirements of the sample. This can
comprise a collection of different sample bottle types for a range of analysis. These
shall be collected in accordance with the methods shown in section 7.
Sample bottles must be labelled in advance of each sampling visit to avoid
inadvertent mislabeling during sample collection. The correct order of sampling
steps is as follows:
1. Initial checks
2. Plumbing metals sample
3. Preparation of the tap
4. [On site tests, where relevant*]
5. After flush chemistry samples
6. Disinfection of the tap
7. Microbiological samples
* Where the water is chlorinated chlorine residual readings should be taken at this
point. Other on-site tests that may be carried out for the purposes of good practise
at this point include temperature, taste, odour, and appearance. It is not however a
requirement for samplers to demonstrate competency in on-site testing as part of
the BS EN ISO/IEC 17024 scheme.
14
Section 7 – Sampling methods
The sampling methods in this section are described in the order they must be
taken.
Failure to follow the correct procedure and the sampling methods prescribed
in the manual could result in samples being unrepresentative of the supply
and result in unnecessary investigations and remedial work.
All procedures must be carried out by trained and carried out only by samplers
certified under the accredited sampling scheme.
Samples should be collected from a suitably representative tap supplying water used
for human consumption or, as relevant, at the point at which it is used in any food
production undertaking.
7.1 Initial checks
• Ensure that the correct property is being sampled, as well as
correct location within the property.
• Ensure that the tap type and condition is likely to provide a sample
that is representative of the supply. Record any observations where
representativeness might be compromised, for example, unhygienic
surroundings, tap hoses and attachments/anti-splash devices in use.
• Check for, and make a note of, any in-line filters, point of use
devices or softeners before sampling.
7.2 Plumbing metals (lead, copper, nickel)
The Regulations require that these parameters are analysed from a one litre
volume “random daytime sample.” This means that the sample must
represent the first 1 litre of water that is run from the tap before any cleaning
or flushing of it, and prior to any other samples being taken from it. It can be
taken at any time within a 24 hour period.
• Do not clean or flush the tap.
• Do not rinse the bottle first.
Where timed actions are required for investigational purposes, time
should be measured using a suitable digital instrument, for example, a
stopwatch. Time durations must not be estimated.
15
• Collect the first litre of water from the tap.
Where a timed investigational stagnation sample for plumbing metals is being
taken for investigation purposes, it should be collected in the manner shown in
Appendix B.5.
7.3 Tap preparation
Clean the outside of the tap with 70% isopropyl alcohol wipe to remove any
debris, grease or other potential sample contaminants. Note: this does not
constitute disinfection of the tap. See section 8.1 for instructions on tap
disinfection
• Remove anti-splash devices or rubber hoses etc. where practicable and with the
permission of the premises owner or their representative.
• Turn the tap on and adjust the flow. Run for a minimum of two
minutes.
• Where the supply is chlorinated, take an on-site test measurement at
the start and at the end of sampling to verify that the concentration
has not changed.
7.4 Chemistry
This section contains the procedures for the taking of samples for all Regulatory
Group A and Group B chemistry parameters. Group B parameters are the
parameters listed in Parts 1 and 2 (of schedule 1 of the Regulations).
The sampler must add the sampling procedures for each of these parameters
into their local sampling manual as part of their certification. Bottles for
chemical analysis should be filled in accordance with the instruction of the
accredited analytical laboratory. They must be the methods of the accredited
laboratory performing the analysis to ensure that sample collection and
transport is consistent with the accredited analytical method.
Include sampling procedures for the following parameters:
Metals other than mercury and plumbing metals
Pesticides
Trihalomethanes (THMS)
16
Polyaromatic hydrocarbons (PAH)
Mercury and alpha and beta samples
Sulphide
General chemistry parameters
Radon
Taste and odour
Section 8 – Microbiological sampling
Following tap preparation and all relevant chemistry samples, turn off the tap
and carry out the following procedures using a 10000mg/l chlorine solution:
8.1 Disinfection of tap
N.B. For purposes of best practice this method employs a double
disinfection procedure:
• Following flush and completion of any chemical sampling turn tap off.
• Inject - a pre-prepared chlorine solution (see section 5) over and into
the tap nozzle using a suitable container product (for example, a
laboratory-style wash bottle). Leave the solution for a contact time of
two minutes. (the make and model of the vessel or container used
must be listed in the appended equipment list).
• Turn on the tap and adjust the flow to a steady stream.
• Run for one minute, then turn off the tap.
• Re-apply the disinfectant and leave for a minimum of two minutes.
• Turn on the tap and adjust flow to steady stream.
• Run the tap for a minimum of two minutes.
8.2 Microbiological sampling procedure
(Usually a pre-prepared 500 ml sterilised clear plastic bottle with added
sodium thiosulphate):
• Clean hands with antibacterial hand gel / hand wipes. Consider
17
wearing disposable single use hygienic gloves.
• Using the bacterial bottle type shown in the appendix of this manual,
hold it near its base and unscrew cap.
• Do not put the cap down. Hold it open end downwards.
• Do NOT rinse the bottle.
• Fill the bottle by holding it under the water stream a slight angle.
• Avoid splashing and fill to the line where the cap meets the bottle
so as to leave an air space to allow for expansion during
transportation.
• Replace the cap taking care not to touch the inside of the cap or it
to come into contact with anything.
• Tighten the cap and invert.
• Transfer to and transport in a refrigerated unit or cool box.
18
Section 9 – Storage and transportation of samples
Samples must be transferred to a vehicle fridge, refrigerated vehicle or cool box,
which must be maintained at 2-8 ̊C after being taken, until delivery to the
laboratory. The analytical laboratory can advise on any other bottles requiring
refrigeration. Where cool boxes are used, a sufficient number of frozen ice packs
must be placed within the cool box during the transportation of samples to ensure
the temperature remains within the required temperature range.
Complete the “Chain of custody record” using the sampler’s local proforma, a copy of
which should be appended to the samples, for each crate of sample bottles to be
transferred to the laboratory and place it into the crate. The sampler may retain a
copy for their own record.
Where samples are transferred to a third party, for example a courier, crates should
then be sealed, to prevent any tampering of samples during transit unless.
The microbiological characteristics of a sample can change significantly when stored,
even for relatively short periods of time. Samples should, therefore, be analysed as
soon as practicable on the day of collection and once taken be stored in the dark in
the temperature range of 2-8 °C. In any event, the analysis should commence within
24 hours of the sample being taken.
The samples must be transferred to the laboratory as soon as practicable on the day
of collection, for analysis to commence promptly on arrival, whilst taking account of
parameter stability times – ideally within 24 hours. In exceptional circumstances, if
there is a delay, store the samples in a secure fridge at 2-8 ºC for analysis within eight
hours the next day. Samples that do not meet these requirements may not be
processed. Samples must remain upright at all times whilst in transit. Raw
(untreated) water investigational samples and samples from the tap taken for
regulatory purposes should be segregated to prevent contamination.
If samples are unable to be received by the laboratory on the day of sampling, they
must be stored securely and transported to the laboratory the following morning.
The temperature of fridges and cool boxes used for transporting samples should
remain stable and within 2 °C and 8 °C during their transportation. This should be
monitored with a calibrated maximum minimum thermometer. The thermometer
should be placed into the cool box/fridge and the temperature recorded once a
stabilised reading is displayed. A data logger should be used, and the data
downloaded on a daily basis and checked, to ensure the temperature has been
maintained between the correct range.
Short-lived variations below 2 °C and above 8 °C are to be expected as the
fridge/cool box is opened. Occasions lasting over one hour should be noted. These
variations can be minimised by buffering the thermometer/probe in a small
container of liquid to avoid spurious readings such as when the cool box or fridge is
opened to add samples.
19
Ideally the temperature should be recorded using a thermometer that records the
maximum and minimum temperatures for the period that the samples are stored
and transported by the sampler. The temperature must be noted on the sampler’s
record sheet. Any recordings outside of the range 2-8 °C should be notified to the
laboratory quality control manager, so that corrective action can be taken.
Where the samples are transported to the laboratory by a courier, the temperature
of the courier fridge and/or depot fridge must be recorded on a record sheet. An
example of a record sheet can be found in Appendix A8. Arrangements must be
made for the courier to deliver the samples to the laboratory, as soon as is
practicable.
Cool boxes should be cleaned using a suitable commercial disinfectant product prior
to the sampling visit, either on the day or evening before.
20
Appendices
Appendix A
A1. On site testing
It is not a requirement under BS EN ISO/IEC 17024 scheme to demonstrate
competency in the following procedures. These are provided for guidance only.
Note, it is recommended that all instrumentation used for on- site testing is
regularly calibrated (see Appendices A2 and A7).
A2. Procedure for temperature readings
Water temperature readings should be taken using a suitable thermometer,
according to the manufacturer’s instructions. These may vary according to the make
and model. The thermometer should have a range between 0 °C and 100 °C and be
capable of reading to within 0.1 °C over the range of use.
All digital thermometers should be calibrated as per manufacturer’s instructions
before they are used. Thereafter they shall be calibrated according to manufacturer’s
instructions every 12 months. This should be in accordance with the appropriate
British Standard. Calibration shall consist of measuring temperature in an ice bath,
and in boiling water. Thermometers that do not read 0 °C and 100°C respectively
shall be replaced with a new thermometer.
• Take any pre-flush temperature readings for any investigational sampling
required.
• Flush the tap for a minimum of three minutes.
• Place a beaker under the tap and run water into it until it overflows.
• Turn on the thermometer and immerse the probe into the water in the
beaker. Do not immerse above the probe.
• Allow the temperature to stabilise then record the thermometer reading
as shown on the unit.
• If the temperature recorded appears abnormally high or low, then repeat
the check and record the temperature once it has stabilised.
• Where the temperature remains abnormally high, an investigation should be
carried out to determine the cause and extent. Following this the local
authority will need to ensure that the relevant persons (as defined in section
80 of The Water Industry Act 1991) carries out the necessary remedial action
to prevent a recurrence and subsequently verifies completion in a timely
These appendices are intended to provide guidance on current best practice
and to assist with investigations or other types of sampling
21
manner.
A3. Chlorine residual measurements
The measurement of chlorine residual is only applicable where the supply is known
or suspected to be disinfected or pre-treated with a chlorine disinfectant, such as
sodium hypochlorite.
Methods will vary according the instructions of the device and manufacturer’s model.
The manufacturer’s instructions must be followed in all cases. The sampler should
insert the procedures for the instrument used in accordance with the manufacturer’s
instructions into this document.
A3.1 NN-Diethyl-p-phenylenediamine (DPD) reagents (DPD)
DPD measures chlorine that is not bound chemically to other compounds (“free”
chlorine). The addition of DPD to chlorinated water forms a pink/red colour, which is
measurable.
To measure “total” chlorine (free chlorine and chlorine which has become
chemically bound to other components, known as “combined” chlorine), the DPD is
used with iodide, which reacts with DPD to give a measurable pink/red colour,
proportional to the total chlorine concentration.
After flushing the tap for three minutes, carry out the following procedures as
required.
A4. Visual appearance
• Take an untreated 1 L taste and odour bottle and rinse the bottle and stopper
under the tap twice.
• By holding under a running tap half fill the taste and odour bottle and
replace the stopper.
If stored in a clean dry environment liquid DPD has a shelf life of twelve
months whilst unopened and one month when opened. The reagent
container should be refrigerated once opened. The expiry date of one month
from the date of opening must be written on every bottle where it is used,
once it has been opened. Discard any liquid DPD bottles which are outside
this date. Check that the DPD reagents in use have a legible batch number
and expiry date by the manufacturer. Discard any bottles where the batch
number or expiry date is illegible.
Vessel types for this test may vary and the method should be checked by the
laboratory supplier. The procedure should be amended locally as required.
22
• Invert the bottle and shake vigorously.
• Hold the bottle up to the light and inspect the contents for any
particulates, turbidity/cloudiness or colour.
• Note the appearance of the water.
• Record the results of your observations.
A5. Procedure for field odour test
• After completing the visual test remove the stopper and immediately smell
the sample.
• Note and record any abnormal odour or absence of odour.
• Discard the sample unless carrying out a taste test.
A6. Procedure for taste test (optional)
• Pour a small portion of the original odour sample into a beaker and rinse.
• Discard the water in the beaker.
• Pour approximately 125 ml of the original odour sample into the beaker. Taste
the sample.
• Note and record any abnormal taste, or absence of taste.
A7. Test equipment checks
Test equipment must be checked and calibrated in accordance with manufacturer’s
instructions to ensure the equipment remains fit for purpose.
A8. Proformas
The following proformas must be appended to the local authority version of the
scheme manual. These may be adapted locally but must contain the same
information as those in the example proformas embed below.
• Manual change request form
• Chain of custody form
• Authorisation to carry out sampling
If an unusual odour is detected; caution should be applied when proceeding
to tasting the water.
23
• Daily check for vehicle and refrigerated storage
• Sample storage fridge temperature and cleaning record
• Sample bottle image list and their descriptions (sampler to add their own list)
• Sampler’s local equipment list (sampler to add their own list)
24
Private Water supplies Sampling Procedures Manual
version number:
Issue date:
Private Water Supplies - Sampling Procedures Manual Change
request form
Sampler contact name:
Sampler contact email and phone number:
Section of manual that the change refers to (including page number):
Reason for the requested change:
Further details of the requested change to be described below:
30
Private Water supplies Sampling Procedures
Manual
version number: 1
SECTION
page of
Issue date:
Sample Chain of Custody record
Each crate must be accompanied by only one of these sheets. It must be completed at 2
stages to form a record of the sample handling process from the time at which the crate
is sealed at the courier point to when it is unsealed and the samples received at the
laboratory.
Crate identity number:
On the reverse of this sheet write the identification numbers of the samples placed in
the crate accompanied by this sheet (or stick on labels with the identification numbers)
TO BE COMPLETED ON FILLING THE CRATE
Courier point location…………………………………………………………………………
Name of person loading crate…………………………………………………………………
Local authority/organisation name……………………………………………………………
Contact phone number of above……………………………………………………………..
Signature of person loading the crate…………………………………………………………
Time crate sealed………………………………………………………………………………
Date crate sealed…………………………………………………………………....................
No of microbiology samples in crate
No. Chemistry bottle in crate…………….
No. of other bottles in crate………………
TOTAL No. BOTTLES…………………..
2. TO BE COMPLETED ON ARRIVAL AT LABORATORY
Date samples arrived at sample reception………………………………………………..
Time samples arrived at sample reception…………………………………………………
Name of laboratory……………………………………………………………………………
Samples registered by (insert name)…………………………………………………………..
I confirm that [ ] bottles (insert total no.) have been received, and that the sample identification numbers
correspond to those on the reverse of this sheet.
No. bottles broken or missing……………………
Signature of the above named ………………………………………………………
31
Private Water supplies Sampling Procedures Manual
version number: 1
SECTION: Appendix 1
page 1 of 1
Issue date:
AUTHORISATION TO CARRY OUT SAMPLING
Name of sampler
Post
Date of Appointment
Present location and date
Date of training
Date of assessment by Certification
Body
Sample procedures manual number
and issue date
Technical Manager Declaration
I confirm this person has undergone a full training/ review/ audit (delete as appropriate) and I authorise this person
to carry out the statutory and or operational/commercial sampling on behalf of the local authority. I also confirm
that I have provided the tools, equipment and PPE required for sampling in accordance with the procedures in this
manual
Technical Manager signature and date
32
Private Water supplies Sampling Procedures
Manual
version number: 1
SECTION
page of
Issue date:
Daily check for vehicle and refrigerated storage
Vehicle type/registration
Fridge/cool box Serial/Equipment
No.
Thermometer serial no./type
Note
This is only to be filled in on days when cool box is being used. On days when not
being used record “n/a” against date. A min/max thermometer should be used and
min/max temperatures reset at the start of the day and recorded at the end of the
sample round.
Month: Year: Required range: 2-8 °C
Date
Fridge/
cool box
cleaned
Initial
Min temperature
Max temperature
Initial
Comments
1
st
2
nd
3
rd
4
th
5
th
6
th
7
th
8
th
9
th
10
th
11
th
12
th
13
th
14
th
15
th
16
th
33
17
th
18
th
19
th
20
th
21
st
22
nd
23
rd
24
th
25
th
26
th
27
th
28
th
29
th
30
th
31
st
34
Private Water supplies Sampling Procedures
Manual
version number: 1
SECTION
page of
Issue date:
Sample storage fridge temperature and cleaning record
Site
Month
Year
Thermometer
Type/No.
Fridge type/ no.
Thermometer working
range
2-8 °C
Date
Start
Time
Start Temp
°C
Fridge/storage
(cleaned/not
cleaned)
Initial
End
Time
Maximum
and
minimum
temp °C
Temp
in
range
2 to 8
°C?
(Y/N)
Initial
1st
2nd
3rd
4th
5th
6th
7th
8th
9th
10th
11th
12th
13th
35
14th
15th
16th
17th
18th
19th
20th
21st
22nd
23rd
24th
25th
26th
27th
28th
29th
30th
31st
On days where fridge/storage is not used start/end times should be recorded as “n/a”
Comments
36
The following proformas are provided as examples only. It is not a requirement of the
BS BS EN ISO/IEC 17024 scheme that these are appended to the local authority
version of the scheme manual:
• Calibration record for hand held Chlorometer.
• Daily check for hand held Chlorometer.
• Calibration record for field thermometer.
• Calibration record for reference thermometer.
• Daily check for hand held instrumentation.
• Calibration record for primary thermometer.
37
Private Water supplies Sampling Procedures
Manual
version number: 1
SECTION
page of
Issue date:
Calibration record for hand held Chlorometer
Instrument name (in full):
Meter Serial/Equipment No.
Date of Calibration:
Reason for Calibration
Calibration Standard type and batch
no.
1
st
standard value (low)
2
nd
standard value (medium)
Recorded value on instrument
3
rd
standard value (high)
Recorded value on instrument
Calibration successful? Y/N
Recorded value on instrument
Checked against standard
Comments:
Within acceptable range? Y/N
Date of Calibration:
Reason for Calibration
Calibration Standard type and batch
no.
1
st
standard value (low)
2
nd
standard value (medium)
3
rd
standard value (high)
Recorded value on instrument
Calibration successful? Y/N
Recorded value on instrument
Checked against standard
Recorded value on instrument
Comments:
Within acceptable range? Y/N
Date of Calibration:
38
Reason for Calibration
Calibration Standard type and batch
no.
1
st
standard value (low)
2
nd
standard value (medium)
Recorded value on instrument
3
rd
standard value (high)
Recorded value on instrument
Calibration successful? Y/N
Recorded value on instrument
Checked against standard
Comments:
Within acceptable range? Y/N
Note: Instruments should be calibrated according to manufacturer’s instructions
39
Private Water supplies Sampling Procedures
Manual
version number: 1
SECTION
page of
Issue date:
Daily check for hand held Chlorometer
Instrument name (in full):
Meter Serial/Equipment No.
Standard used
Batch number
Target value, limits and units
Date of last calibration
Date of next calibration
Date
Instrument
reading
Within
Acceptable
Range?
(Yes/No)
Initial
Comments
Date
Instrument
reading
Within
Acceptable
Range?
(Yes/No)
Initial
Comments
1
st
17
th
2
nd
18
th
3
rd
19
th
4
th
20
th
5
th
21
st
6
th
22
nd
7
th
23
rd
8
th
24
th
9
th
25
th
10
th
26
th
11
th
27
th
12
th
28
th
13
th
29
th
14
th
30
th
15
th
31
st
16
th
Note: This is only to be filled in on days when instrument is used. On days when not being used record “n/a”
against date. Manufacturer’s instructions for calibration must be followed.
40
Private Water supplies Sampling Procedures
Manual
version number: 1
SECTION
page of
Issue date:
Calibration record for field thermometer
Reference
Thermometer
Type and serial
No.
Field
thermometer
Type and serial
No.
Date of
calibration
Calibrated by
Comments
0 °C calibration
recorded
temperature
reference/ field
thermometer
100 °C calibration ok
recorded
temperature
reference/ field
thermometer
Note: Field thermometer is calibrated against reference thermometer every 12 months.
Calibration points are 0 °C and 100 °C. Both thermometers are immersed and any deviation noted in
the comments.
41
Private Water supplies Sampling Procedures
Manual
version number: 1
SECTION
page of
Issue date:
Calibration record for reference thermometer
Reference
Thermometer
Type and serial No.
Frequency of calibration
Required tolerance
Date of calibration
Calibrated by
Comments (including whether the required tolerance
was met)
Note: It is expected that the reference thermometer will be sent for external calibration by an accredited calibration
laboratory and used as a reference to calibrate thermometers used in the field.
42
Private Water supplies Sampling Procedures
Manual
version number: 1
SECTION
page of
Issue date:
Daily check for hand held instrumentation
Instrument name (in full):
Meter Serial/Equipment No.
Standard used
Batch number
Standard measurement and unit
Date of last calibration
Date of next calibration
Date
Instrument
reading
Within
acceptable
range?
(Yes/No)
Initial
Comments
Date
Instrument
reading
Within
acceptable
range?
(Yes/No)
Initial
Comments
1
st
17
th
2
nd
18
th
3
rd
19
th
4
th
20
th
5
th
21
st
6
th
22
nd
7
th
23
rd
8
th
24
th
9
th
25
th
10
th
26
th
11
th
27
th
12
th
28
th
13
th
29
th
14
th
30
th
15
th
31
st
16
th
Note: This is only to be filled in on days when instrument is used. On days when not being used record “n/a”
against date. Manufacturer’s instructions for calibration must be followed.
43
Private Water supplies Sampling Procedures
Manual
version number: 1
SECTION
page of
Issue date:
44
Appendix B
The sampling information and procedures in this section are not part of the BS EN
ISO/IEC 17024 accredited scheme. They are provided here for the purpose of
assisting samplers in the collection of samples for investigatory purposes.
Regulation 16 in England and regulation 18 in Wales, of the respective regulations,
require that a local authority must carry out an investigation to establish the cause if
it suspects that a private water supply is unwholesome or that an indicator
parameter does not comply with the concentrations or values prescribed in the
relevant schedules. Such investigations may include sampling at points on a supply
other than the point of consumption and/or for parameters that are additional to
those that have breached a regulatory standard.
Investigational sample types – As shown in section A of this manual, regulatory
samples, with the exception of those for plumbing metals, must be taken following
the preparation of the tap, either prior to flushing (for plumbing metals) or after
flushing, and in the case of microbiological samples, after disinfecting the tap. For
the purposes of investigations however, the following other sample types can be
used:
(a)
Overnight stagnation samples – These samples give a measure of the
potential conditions for the dissolution of metals or microbiological growth
within plumbing systems, after an overnight period in which the water could
have remained static in pipework. Ideally these samples are taken prior to any
consumer use, and before any preparative flushing, cleansing or disinfection
of the tap as part of an investigation. The sample bottle must not be rinsed
out before filling.
(b)
Pre–flush samples – These sample types are taken prior to any flushing,
cleansing or disinfection of a tap at a random point in any 24hour period.
Microbiological samples of this type may also be accompanied by a swab to
determine biofilm/ growth within fittings. In these instances, the swab must
be taken before cleaning/cleansing the tap and the taking of any other
samples.
Pre-flush chemistry samples may also be useful in certain circumstances,
notably for investigating or confirming the occurrence of plumbing metals on a
domestic distribution system, such as lead, copper, nickel or indeed iron. The
results of these samples can be compared with post flush samples (either
Swabs need to be moistened to effectively pick up material and to
maintain viability of organisms. Usually the tap has some residual
water from its last use, if not, it can be opened just enough to wet the
end of the tap.
45
regulatory or investigational) for the same parameters. Post flush samples for
chemical analysis must be taken prior to microbiological samples.
(c)
Lead stagnation samples – samples of this type may be collected for
investigative purposes to measure the lead content in water after it has been
static in lead pipework for a defined period. (See Appendix B.2 for procedure).
B.1
Procedure for sampling raw water from an open water source
This procedure is applicable for taking investigational samples from any open water
facility. This includes from rivers and streams, chambers, channels and storage
reservoirs (and tanks) where sampling can only be achieved by standing over open
water from a height. Samplers should be aware when undertaking microbiological
sampling this method poses contamination risks and health and safety hazards.
When sampling at height, all appropriate local health and safety procedures must be
adhered to. Single use Disposable gloves must be worn when taking microbiological
samples (for example, large volume samples). Where there is a risk of falling into open
water, always wear a life jacket.
• When working from height, direct filling of sample bottles, other than
samples for pathogens and viruses is not advised. It requires the use of a
dipping jug on a chain.
• First find a suitably safe place to take the sample without causing risk of
injury. This may be a bridge, platform or jetty.
• Check that the jug is clean, dry and not contaminated.
• Lower the jug and allow it to sink well below the surface. Do not allow the
jug to hit the bottom surface. to avoid disturbance of any sediment or
biofilm, etc.
• Draw the jug back. Rinse water around the inner surfaces of the jug and
discard the water away from or downstream from the sample point.
• Lower jug as before and draw jug back.
• Fill sample bottles without delay by pouring from the jug, observing any
specific requirements of the bottle type. (Any rinsing to be disposed away
from or downstream of the sample point).
46
B.2
Procedure for lead stagnation sampling
Lead stagnation samples represent the concentration of lead in the sample after the
water has been left in contact with pipes for a specified duration (for example, 30
minutes). This is to assist with determining the level of risk posed by plumbing and
any lead pipes and/or fittings.
These samples must be collected at point 2 in the order of sampling shown in
section 6 using a plastic bottle that is at least 1 L in volume.
• Explain to consumer that they will be unable to use the tap for a specified
period due to stagnation method.
• The tap must be first flushed for a minimum of two minutes and
the temperature checked throughout flushing.
• When the temperature has stabilised turn off the tap.
• Do not turn on the tap for 30 minutes.
• Collect the first litre of water without first rinsing the bottle and then screw
on the cap.
• Transfer to and transport in a refrigerated unit or cool box.
