The Water Supply (Water Quality) Regulations 2016

Regulation 2

SCHEDULE 1 E+W Prescribed concentrations and values

Table A

Microbiological parameters

Part I: Directive requirements

(1)	(2)	(3)	(4)	(5)
Item	Parameters	Concentration or value (maximum)	Units of measurement	Point of compliance
1.	Enterococci	0	number/100ml	Consumers' taps
2.	Escherichia coli	0	number/100ml	Consumers' taps
	(E. coli)

Part II: National requirements

1 Compliance required as to 95% of samples from each service reservoir (regulation 4(6)).
(1)	(2)	(3)	(4)	(5)
Item	Parameters	Concentration or value (maximum)	Units of measurement	Point of compliance
1.	Coliform bacteria	0	number/100ml	Service reservoirs1 and water treatment works
2.	Escherichia coli (E. coli)	0	number/100ml	Service reservoirs and water treatment works

Table B

Chemical parameters

Part I: Directive requirements

1 The parametric value refers to the residual monomer concentration in the water as calculated according to specifications of the maximum release from the corresponding polymer in contact with the water. This is controlled by product specification.
2 See also regulation 4(2)(d).
3 See the definition of “pesticides and related products” in regulation 2.
4 The parametric value applies to each individual pesticide.
5 “Pesticides: total” means the sum of the concentrations of the individual pesticides detected and quantified in the monitoring procedure.
6 The specified compounds are— The specified compounds are— — benzo(b)fluoranthen; — benzo(k)fluoranthene; — benzo(ghi)perylene; — indeno(1,2,3-cd)pyrene. The parametric value applies to the sum of the concentrations of the individual compounds detected and quantified in the monitoring process.
7 The parametric value applies to the sum of the concentrations of the individual compounds detected and quantified in the monitoring process.
8 The specified compounds are— The specified compounds are— — chloroform; — bromoform; — dibromochloromethane; — bromodichloromethane The parametric value applies to the sum of the concentrations of the individual compounds detected and quantified in the monitoring process.
(1)	(2)	(3)	(4)	(5)
Item	Parameters	Concentration or value (maximum)	Units of measurement	Point of compliance
1.	Acrylamide	0.10	µg/1	1
2.	Antimony	5.0	µgSb/1	Consumers' taps
3.	Arsenic	10	µgAs/1	Consumers' taps
4.	Benzene	1.0	µg/1	Consumers' taps
5.	Benzo(a)pyrene	0.010	µg/1	Consumers' taps
6.	Boron	1.0	mgB/1	Consumers' taps
7.	Bromate	10	µgBrO3/1	Consumers' taps
8.	Cadmium	5.0	µgCd/1	Consumers' taps
9.	Chromium	50	µgCr/1	Consumers' taps
10.	Copper	2.0	mgCu/1	Consumers' taps
11.	Cyanide	50	µgCN/1	Consumers' taps
12.	1, 2 dichloroethane	3.0	µg/1	Consumers' taps
13.	Epichlorohydrin	0.10	µg/1	1
14.	Fluoride	1.5	mgF/1	Consumers' taps
15.	Lead	10	µgPb/1	Consumers' taps
16.	Mercury	1.0	µgHg/1	Consumers' taps
17.	Nickel	20	µgNi/1	Consumers' taps
18.	Nitrate2	50	mgNO3/1	Consumers' taps
19.	Nitrite2	0.50	mgNO2/1	Consumers' taps
		0.10		Treatment works
20.	Pesticides34	0.030	µg/1	Consumers' taps
	Aldrin
	Dieldrin	0.030	µg1	Consumer's taps
	Heptachlor
	Heptachlor epoxide
	Other pesticides	0.10	μg/l	Consumers' taps
21.	Pesticides: total5	0.50	µg/1	Consumers' taps
22.	Polycyclic aromatic hydrocarbon6	0.10	µg/1	Consumers' taps
23.	Selenium	10	µgSe/1	Consumers' taps
24.	Tetrachloroethene and Trichloroethene7	10	μg/l	Consumers' taps
25.	Trihalomethanes: Total8	100	µg/1	Consumers' taps
26.	Vinyl chloride	0.50	µg/1	1

Part II: National requirements

(1)	(2)	(3)	(4)	(5)
Item	Parameters	Concentration or value (maximum)	Units of measurement	Point of compliance
1.	Aluminium	200	µgA1/1	Consumers' taps
2.	Colour	20	mg/1 Pt/Co	Consumers' taps
3.	Iron	200	µgFe/1	Consumers' taps
4.	Manganese	50	µgMn/1	Consumers' taps
5.	Odour	Acceptable to consumers and no abnormal change		Consumers' taps
6.	Sodium	200	mgNa/1	Consumers' taps
7.	Taste	Acceptable to consumers and no abnormal change		Consumers' taps
8.	Tetrachloromethane	3	µg/1	Consumers' taps
9.	Turbidity	4	NTU	Consumers' taps

Regulation 2

SCHEDULE 2 E+W Indicator parameters

1 The water should not be aggressive.
2 Where treatment to reduce the level of radionuclides in water intended for human consumption has been taken, monitoring must be carried out to ensure the continued efficacy of the treatment.
3 Remedial action may be taken by the Secretary of State on radiological protection grounds without further consideration and deemed to be justified where radon concentrates exceed 1,000 Bq/1.
4 If tritium concentration exceeds its parametric value, an investigation (which may include analysis) of the presence of artificial radionuclides is required.
5 May be monitored from samples of water leaving treatment works or other supply point, as no significant change during distribution.
(1)	(2)	(3)	(4)	(5)
Item	Parameters	Specification concentration or value (maximum unless otherwise stated) or state	Units of measurement	Point of compliance
1.	Ammonium	0.50	mgNH4/1	Consumers' taps
2.	Chloride1	250	mgC1/	Supply point5
3.	Clostridium	0	Number/100ml	Supply point5
	Perfringens (including spores)
4.	Coliform bacteria	0	Number/100ml	Consumers' taps
5.	Colony counts	No abnormal change	Number/1ml at 22°C	Consumers' taps, service reservoirs and treatment works
6.	Conductivity1	2500	μS/cm at 20°C	Supply point5
7.	Hydrogen ion	9.5 (maximum) 6.5 (minimum)	pH value	Consumers' taps
8.	Indicative dose2	0.10	mSv	Supply point5
	(a) gross alpha	0.1	Bq/1	Supply point5
	(b) gross beta	1	Bq/1	Supply point5
9.	Radon3	100	Bq/1	Supply point
10.	Sulphate1	250	mgSO4/l	Supply point5
11.	Total organic carbon (TOC)	No abnormal change	mgC/l	Supply point
12.	Tritium (for radioactivity)4	100	Bq/l	Supply point5
13.	Turbidity	1	NTU	Treatment works

Regulation 6

SCHEDULE 3 E+W Monitoring

Table 1

Parameters and circumstances for check monitoring

(1)	(2)	(3)
Item	Parameter	Circumstances
1.	Aluminium	When used as flocculant or where the water originates from, or is influenced by, surface waters
2.	Ammonium
3.	Clostridium perfringens (including spores)	Where the water originates from, or is influenced by, surface waters
4.	Coliform bacteria
5.	Colony counts
6.	Colour
7.	Conductivity
8.	Escherichia coli (E. coli)
9.	Hydrogen ion
10.	Iron	When used as flocculant or where the water originates from, or is influenced by, surface waters
11.	Manganese	Where the water originates from, or is influenced by, surface waters
12.	Nitrate	When chloramination is practised
13.	Nitrite	When chloramination is practised
14.	Odour
15.	Taste
16.	Turbidity

Table 2

Annual sampling frequencies: water supply zones

Note: This table sets out the annual sampling frequencies for all the substances and parameters in column 1. These are determined for each water supply zone according to its estimated population (column 2). The number of samples is either the standard number in column 4 or the reduced number in column 3 (if one is given). Regulation 9 provides for the circumstances in which the reduced number of samples may be taken.

1 Where the population is not an exact multiple of 5,000, the population figure must be rounded up to the nearest multiple of 5,000.
2 Sampling for these parameters may be within water supply zones or at supply points as specified in Table 3, subject to footnotes (iii) and (iv) below.
3 Check monitoring in water supply zones is required only where chloramination is practised. In other circumstances audit monitoring is required.
4 Audit monitoring in water supply zones is required only where sodium hypochlorite is added after water has left the treatment works. In other circumstances, audit monitoring is required at supply points.
5 To monitor for indicative dose.
6 In the event that a single sample is taken in a year, a further sample should be taken if there is any change in relation to that supply that could affect the concentration of radionuclides in the water supply.
(1)		(2)	(3)	(4)
Substances and parameters subject to monitoring		Estimated population of water supply zone	Reduced	Standard
Subject to check monitoring
E. coli	<100			4
Coliform bacteria	≥100			12 per 5,000
Residual disinfectant				Population1
Aluminium	<100		1	2
Ammonium	100-4,999		2	4
Clostridium perfringens	5,000-9,999		6	12
(including spores)	10,000-29,999		12	24
Colony counts	30,000-49,999		18	36
Colour	50,000-79,999		26	52
Conductivity2	80,000-100,000		38	76
Hydrogen ion
Iron
Manganese
Nitrate3
Nitrite
Odour
Taste
Turbidity
Subject to audit monitoring
Aluminium	<100			1
Antimony	100-4,999			4
Arsenic	5,000-100,000			8
Benzene2
Benzo(a)pyrene
Boron2
Bromate4
Cadmium
Chromium
Clostridium perfringens
(including spores)
Copper
Cyanide2
1,2 dichloroethane2
Enterococci
Fluoride2
Gross alpha256
Gross beta256
Iron
Lead
Manganese
Mercury2
Nickel
Nitrate3
Nitrite3
Pesticides and related products2
Polycyclic aromatic hydrocarbons
Radon26
Selenium
Sodium
Trichloroethene
Tetrachloroethene2
Tetrachloromethane2
Trihalomethanes
Chloride2
Sulphate2
Total organic carbon2
Tritium26

Table 3

Annual sampling frequencies: treatment works or supply points

Note 1: Sampling is at treatment works for the substances and parameters in column 2 of the Table (items (1) to (6)) and at supply points for the other substances and parameters, except nitrite, subject to footnotes (i) and (iv) to the Table below. Note 2: This Table sets out the annual sampling frequencies for all the substances and parameters in column 2 at treatment works or supply points. The frequencies are determined according to the volume of water supplied at each treatment works or supply point (column 3). The number of samples is either the standard number in column 5 or the reduced number in column 4 (if one is given). Regulation 9 provides for the circumstances in which the reduced number of samples may be taken.

1 Sampling is at treatment works when chloramination is practised.
2 Check monitoring is required only in respect of surface waters (see regulation 6(2) and Table 1 in Schedule 3).
3 Audit monitoring at supply points is required only where sodium hypochlorite is not added after water has left the treatment works. In other circumstances, audit monitoring is required in water supply zones.
4 Sampling at treatment works when chloramination is not practised.
5 To monitor for indicative dose.
(1)	(2)	(3)	(4)	(5)
Item	Substances and parameters	Volume of water supplied m3/d	Reduced	Standard
1.	E. coli	<20	-	4
2.	Coliform bacteria	20–1,999	12	52
3.	Colony counts	2,000–5,999	52	104
4.	Nitrite1	6,000–11,999	104	208
5.	Residual disinfectant	≥12,000	104	365
6.	Turbidity
Subject to check monitoring
7.	Clostridium perfringens 2	<20	-	2
8.	Conductivity	20–999	2	4
		1,000–1,999	6	12
		2,000-5,999	12	24
		6,000-9,999	18	36
		10,000-15,999	26	52
		16,000-32,999	52	104
		33,000-49,999	78	156
		50,000-67,999	104	208
		68,000-84,999	130	260
		85,000-101,999	156	312
		102,000-119,999	183	365
		120,000-241,999	365	730
		242,000–484,999	730	1,460
		485,000–728,999	1,095	2,190
Subject to audit monitoring
9.	Benzene	<20		1
10.	Boron	20–999		4
11.	Bromate3	1,000–49,999		8
12.	Clostridium	50,000–89,999		12
	Perfringens (including spores)	90,000–299,999		24
13.	Cyanide	300,000–649,999		36
14.	1,2 dichloroethane	≥650,000		48
15.	Fluoride
16.	Indicative dose
17.	Mercury
18.	Nitrite4
19.	Pesticides and related products
20.	Radon
21.	Trichloroethene/
	Tetrachloroethene
22.	Tetrachloromethane
23.	Chloride
24.	Sulphate
25.	Total organic carbon
26.	Tritium
27.	Gross alpha5
28.	Gross beta5

Regulation 6

SCHEDULE 4 E+W Monitoring for indicative dose and analytical performance characteristics

Monitoring for compliance with the ID E+W

1.—(1) A water undertaker may use various reliable screening strategies to indicate the presence of radioactivity in water intended for human consumption.

(2) These strategies may include screening for—

(a) certain radionuclides, or screening for an individual radionuclide,

(b) gross alpha activity or gross beta activity screening.

Screening for certain radionuclides or for an individual radionuclide E+W

2.—(1) If one of the activity concentrations exceeds 20% of the corresponding derived value or the tritium concentration exceeds its parametric value listed in Schedule 2, an analysis of additional radionuclides is required.

(2) In deciding which radionuclides are required to be measured for each supply, a water undertaker must take into account all relevant information about likely sources of radioactivity.

Screening strategies for gross alpha activity and gross beta activity E+W

3.—(1) A water undertaker may use a screening strategy for gross alpha and gross beta to monitor for the parametric indicator value for indicative dose.

(2) Subject to paragraph (3), the recommended screening values are—

(a) 0.1Bq/l for gross alpha activity;

(b) 1.0Bq/l for gross beta activity M1 .

(3) If the gross alpha activity exceeds 0.1Bq/l or the gross beta activity exceeds 1.0Bq/l, analysis for specific radionuclides is required.

(4) The Secretary of State may set alternative screening levels for gross alpha activity and gross beta activity where it can be demonstrated by the water undertaker that the alternative levels are in compliance with an ID of 0.1 mSv.

(5) The radionuclides to be measured must be based on all relevant information about likely sources of radioactivity.

Marginal Citations

M1 Where appropriate gross beta activity may be replaced by residual beta activity after subtraction of the K-40 activity concentration.

Calculation of the ID E+W

4.—(1) The ID must be calculated from—

(a) the measured radionuclide concentrations and the dose coefficients laid down in Table A in Annex III to Council Directive 96/29/Euratom laying down basic safety standards for the protection of the health of workers and the general public against the dangers arising from ionising radiation M2 , or

(b) more recent information recognised by the Secretary of State, on the basis of the annual intake of water (730 litres for adults).

(2) Where the following formula is satisfied, it can be assumed that the ID is less than the parametric value of 0.1 mSv and no further investigation is required—

where—

“C_i(obs)” means observed concentration of radionuclide I;

“C_i(der)” means derived concentration of radionuclide i;

“n” means number of radionuclides detected.

Table 1

Derived concentrations for radioactivity in water intended for human consumption

This table includes values for the most common natural and artificial radionuclides: these are precise values, calculated for a dose of 0.1 mSy, an annual intake of 730 litres and using the dose coefficients laid down in Table A of Annex III to Council Directive 96/29/ Euratom. Derived concentrations for other radionuclides can be calculated on the same basis, and values can be updated on the basis of more recent information recognised by the Secretary of State

1 This Table allows only for the radiological properties of uranium, not for its chemical toxicity.
(1)	(2)	(3)
Origin	Nuclide	Derived concentration
Natural:	U-2381	3.0 Bq/1
	U-2341	2.8 Bq/1
	Ra-226	0.5 Bq/1
	Ra-228	0.2 Bq/1
	Pb-210	0.2 Bq/1
	Po-210	0.1 Bq/1
Artificial:	C-14	240 Bq/1
	Sr-90	4.9 Bq/1
	Pu-239/Pu-240	0.6 Bq/1
	Am-241	0.7 Bq/1
	Co-60	40 Bq/1
	Cs-134	7.2 Bq/1
	Cs-137	11 Bq/1
	1-131	6.2 Bq/1

Table 2

Performance characteristics and methods of analysis

For the following parameters and radionuclides, the method of analysis used must, as a minimum, be capable of measuring activity concentrations with a limit of detection specified below.

(1)	(2)	(3)
Parameters and radionuclides	Limit of detection (Notes 1, 2)	Notes
Tritium	10 Bq/1	Note 3
Radon	10 Bq/1	Note 3
gross alpha activity	0.04 Bq/1	Note 4
gross beta activity	0.4 Bq/1	Note 4
U-238	0.02 Bq/1
U-234	0.02 Bq/1
Ra-226	0.04 Bq/1
Ra-228	0.02 Bq/1	Note 5
Pb-210	0.02 Bq/1
Po-210	0.01 Bq/1
C-14	20 Bq/1
Sr-90	0.4 Bq/1
Pu-239/Pu-240	0.04 Bq/1
Am-241	0.06 Bq/1
Co-60	0.5 Bq/1
Cs-134	0.5 Bq/1
Cs-137	0.5 Bq/1
I-131	0.5 Bq/1

Note 1: The limit of detection must be calculated according to the ISO standard 11929: Determination of the characteristic limits (decision threshold, detection limit, and limits of confidence interval) for measurements of ionising radiation – Fundamentals and application, with probabilities of errors of 1st and 2nd kind of 0.05 each M3 .

Note 2: Measurement uncertainties must be calculated and reported as complete standard uncertainties, or as expanded uncertainties with an expansion factor of 1.96 according the ISO Guide for the Expression of Uncertainty in Measurement M4 .

Note 3: The limit of detection for tritium and for radon is 10% of its parametric value of 100 Bq/1.

Note 4: The limit of detection for gross alpha activity and gross beta activities are 40% of the screening values of 0.1 and 1.0 Bq/1 respectively.

Note 5: This limit of detection applies only to initial screening for ID for a new water source; if initial checking indicates that it is not plausible that Ra-228 exceeds 20% of the derived concentration, the limit of detection may be increased to 0.08 Bq/1 for routine Ra-228 nuclide specific measurements, until a subsequent re-check is required.

Marginal Citations

M2 OJ No L 159, 29.6.1996, p 1, which is prospectively repealed by Council Directive 2013/59/Euratom (OJ No L 13, 17.1.2014, p 1) from 6th February 2018.

M3 See sections 17A and 219(1) of the Act for the meaning of “licensed water supplier”. This definition is prospectively repealed by paragraph 120 of Schedule 7 to the Water Act 2014 from a date to be appointed.

M4 S.I. 2000/3184, as amended by S.I. 2001/2885, 2002/2469, 2005/2035, 2007/2734, 2010/991, 2013/235, 1387.

Regulation 16

SCHEDULE 5 E+W Analytical methodology

Table A1

Parameters for which, subject to regulation 16(7), methods of analysis are prescribed

(1)			(2)
Parameter			Method
Clostridium perfringens (including spores)			Membrane filtration followed by anaerobic incubation of the membrane on m-CP agar* at 44 & 1°C for 21 & 3 hours. Count opaque yellow colonies that turn pink or red after exposure to ammonium hydroxide vapours for 20 to 30 seconds.
Coliform bacteria			ISO 9308-1
Colony count 22°C-enumeration of culturable microorganisms			PrEN ISO 6222
Colony count 37°C-enumeration of culturable microoganisms			prEN ISO 6222
Enterococci			ISO 7899-2
Escherichia coli (E. coli)			ISO 9308-1
*The composition of m-CP agar is:
Basal medium
Tryptose		30.0g
Yeast extract		20.0g
Sucrose		5.0g
L-cysteine hydrochloride		1.0g
MgSO4·7H2O		0.1g
Bromocresol purple		40.0mg
Agar		15.0g
Water		1,000.0ml
Dissolve the ingredients of the basal medium, adjust pH to 7.6 and autoclave at 121°C for 15 minutes. Allow the medium to cool and add:
D-cycloserine					400.0mg
Polymyxine-B sulphate					25.0mg
Indoxyl- μ -D-glucoside to be dissolved in 8ml sterile water before addition					60.0mg
Filter-sterilised 0.5% phenolphthalein diphosphate solution					20.0ml
Filter-sterilised 4.5% FeCl3·6H2O					2.0ml

Table A2

Parameters in relation to which methods of analysis must satisfy prescribed characteristics

1 The method of analysis must determine total cyanide in all forms.
2 The performance characteristics apply to each individual pesticide and depends on the pesticide concerned.
3 The performance characteristics apply to the individual substances specified at 25% of the parametric value in Part I of Table B in Schedule 1.
4 The performance characteristics apply to the individual substances specified at 50% of the parametric value in Part I of Table B in Schedule 1.
5 The performance characteristics apply to the prescribed value of 4 NTU.
6 The performance characteristics apply to the specification of 1 NTU for water leaving treatment works.
(1)	(2)	(3)	(4)
Parameters	Trueness % of prescribed concentration or value or specification	Precision % of prescribed concentration or value or specification	Limit of detection % of prescribed concentration or value or specification
Aluminium	10	10	10
Ammonium	10	10	10
Antimony	25	25	25
Arsenic	10	10	10
Benzene	25	25	25
Benzo(a)pyrene	25	25	25
Boron	10	10	10
Bromate	25	25	25
Cadmium	10	10	10
Chloride	10	10	10
Chromium	10	10	10
Colour	10	10	10
Conductivity	10	10	10
Copper	10	10	10
Cyanide1	10	10	10
1,2-dichloroethane	25	25	25
Fluoride	10	10	10
Iron	10	10	10
Lead	10	10	10
Manganese	10	10	10
Mercury	20	10	20
Nickel	10	10	10
Nitrate	10	10	10
Nitrite	10	10	10
Pesticides and related products2	25	25	25
Polycyclic aromatic hydrocarbons3	25	25	25
Selenium	10	10	10
Sodium	10	10	10
Sulphate	10	10	10
Tetrachloroethene4	25	25	10
Tetrachloromethane	20	20	20
Trichloroethene4	25	25	10
Trihalomethanes:	25	25	10
Total3
Turbidity5	10	10	10
Turbidity6	25	25	25

Regulation 40(1)

SCHEDULE 6 E+W Amendments

(1)	(2)	(3)	(4)
Regulations to be amended	References	Provisions to be amended	Amendments to be made
The Legislative and Regulatory Reform (Regulatory Functions) Order 2007 M5	S.I. 2007/3544	Part 2 of the Schedule, under the heading “Water”	For “Water Supply (Water Quality) Regulations 2000” substitute “ Water Supply (Water Quality) Regulations 2016 ”
The Water Quality and Supply (Fees) Order 2016	S.I. 2016/303	The Schedule	For “Water Supply (Water Quality) Regulations 2000” substitute “ Water Supply (Water Quality) Regulations 2016 ”

Marginal Citations

M5 There are amendments not relevant to these Regulations.

Regulation 40(2)

SCHEDULE 7 E+W Revocations

(1)	(2)	(3)
Regulations revoked	References	Extent of revocation
The 2000 Regulations	S.I. 2000/3184	The whole Regulations
The Water Supply (Water Quality) (Amendment) Regulations 2001 M6	S.I. 2001/2885	The whole Regulations
The National Health Service Reform and Health Care Professions Act 2002 (Supplementary, Consequential etc. Provisions) Regulations 2002 M7	S.I. 2002/2469	Schedule 1 Part 2 paragraph 91
The Water Act 2003 (Consequential and Supplementary Provisions) Regulations 2005 M8	S.I. 2005/2035	Regulations 3, 10 and 20
The Water Supply (Water Quality) (Amendment) Regulations 2007 M9	S.I. 2007/2734	The whole Regulations
The Legislative and Regulatory Reform (Regulatory Functions) Order 2007	S.I. 2007/3544	The references in Part 2 of the Schedule, under the heading “Water”, to—
		(a) the Water Supply (Water Quality) Regulations 2001; and
		(b) the Water Supply (Water Quality) (Amendment) Regulations 2001
The Water Supply Regulations 2010 M10	S.I. 2010/991	The whole Regulations
The National Treatment Agency (Abolition) and the Health and Social Care Act 2012 (Consequential, Transitional and Savings Provisions) Order 2013 M11	S.I. 2013/235	Paragraph 43 of Schedule 2
The Construction Products Regulations 2013	S.I. 2013/1387	Paragraph 3 of Schedule 5

Marginal Citations

M6 Amended by S.I. 2007/2734.

M7 There are amendments not relevant to these Regulations.

M8 Amended by S.I. 2007/2734.

M9 Amended by S.I. 2013/1387.

M10 Amended by S.I. 2016/573.

M11 There are amendments not relevant to these Regulations.