The Water Supply (Water Quality) Regulations 2001

regulations 2 and 4

SCHEDULE 1 PRESCRIBED CONCENTRATIONS AND VALUES

TABLE A MICROBIOLOGICAL PARAMETERS

Part I:

Directive requirements

Item	Parameters	Concentration or Value (maximum)	Units of Measurement	Point of compliance
1.	Enterococci	0	number/100ml	Consumers' taps
2.	Escherichia coli (E. coli)	0	number/100ml	Consumers' taps

Part II:

National requirements

Item	Parameters	Concentration or Value (maximum)	Units of Measurement	Point of compliance
Note:
* Compliance required as to 95% of samples from each service reservoir (regulation 4(6)).
1.	Coliform bacteria	0	number/100ml	Service reservoirs* 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

Item	Parameters	Concentration or Value (maximum)	Units of Measurement	Point of compliance
Notes:
(i) 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.
(ii) See also regulation 6(6).
(iii) See also regulation 4(2)(d).
(iv) See the definition of “pesticides and related products” in regulation 2.
(v) The parametric value applies to each individual pesticide.
(vi) “Pesticides: Total” means the sum of the concentrations of the individual pesticides detected and quantified in the monitoring procedure.
(vii) The specified compounds are: benzo(b)fluoranthene 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.
(viii) The parametric value applies to the sum of the concentrations of the individual compounds detected and quantified in the monitoring process.
(ix) 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.	Acrylamide	0.10	μg/l	(i)
2.	Antimony	5.0	μgSb/l	Consumers' taps
3.	Arsenic	10	μgAs/l	Consumers' taps
4.	Benzene	1.0	μg/l	Consumers' taps
5.	Benzo(a)pyrene	0.010	μg/l	Consumers' taps
6.	Boron	1.0	mgB/l	Consumers' taps
7.	Bromate	10	μgBrO3/l	Consumers' taps
8.	Cadmium	5.0	μgCd/l	Consumers' taps
9.	Chromium	50	μgCr/l	Consumers' taps
10.	Copper(ii)	2.0	mgCu/l	Consumers' taps
11.	Cyanide	50	μgCN/l	Consumers' taps
12.	1, 2 dichloroethane	3.0	μg/l	Consumers' taps
13.	Epichlorohydrin	0.10	μg/l	(i)
14.	Fluoride	1.5	mgF/l	Consumers' taps
15.	Lead(ii)	(a) 25, from 25th December 2003 until immediately before 25th December 2013	μgPb/l	Consumers' taps
		(b) 10, on and after 25th December 2013	μgPb/l	Consumers' taps
16.	Mercury	1.0	μgHg/l	Consumers' taps
17.	Nickel (ii)	20	μgNi/l	Consumers' taps
18.	Nitrate (iii)	50	mgNO3/l	Consumers' taps
19.	Nitrite (iii)	0.50	mgNO2/l	Consumers' taps
		0.10		Treatment Works
20.	Pesticides (iv)(v) Aldrin ) Dieldrin ) Heptachlor ) Heptachlor ) epoxide )	0.030	μg/l	Consumers' taps
	other pesticides	0.10	μg/l	Consumers' taps
21.	Pesticides: Total (vi)	0.50	μg/l	Consumers' taps
22.	Polycyclic aromatic hydrocarbons (vii)	0.10	μg/l	Consumers' taps
23.	Selenium	10	μgSe/l	Consumers' taps
24.	Tetrachloroethene and Trichloroethene (viii)	10	μg/l	Consumers' taps
25.	Trihalomethanes: Total (ix)	100	μg/l	Consumers' taps
26.	Vinyl chloride	0.50	μg/l	(i)

Part II:

National requirements

Item	Parameters	Concentration or Value (maximum unless otherwise stated)	Units of Measurement	Point of compliance
1.	Aluminium	200	μgAl/l	Consumers' taps
2.	Colour	20	mg/l Pt/Co	Consumers' taps
3.	Hydrogen ion	10.0	pH value	Consumers' taps
		6.5 (minimum)	pH value	Consumers' taps
4.	Iron	200	μgFe/l	Consumers' taps
5.	Manganese	50	μgMn/l	Consumers' taps
6.	Odour	3 at 25°C	Dilution number	Consumers' taps
7.	Sodium	200	mgNa/l	Consumers' taps
8.	Taste	3 at 25°C	Dilution number	Consumers' taps
9.	Tetrachlorome-thane	3	μg/l	Consumers' taps
10.	Turbidity	4	NTU	Consumers' taps

regulations 2 and 4

SCHEDULE 2 INDICATOR PARAMETERS

Item	Parameters	Specification Concentration or Value (maximum) or State	Units of Measurement	Point of monitoring
Notes:
(i) The water should not be aggressive.
(ii) Excluding tritium, potassium-40, radon and radon decay products.
* May be monitored from samples of water leaving treatment works or other supply point, as no significant change during distribution.
1.	Ammonium	0.50	mgNH4/l	Consumers' taps
2.	Chloride (i)	250	mgCl/l	Supply point*
3.	Clostridium perfringens (including spores)	0	Number/100ml	Supply point*
4.	Coliform bacteria	0	Number/100ml	Consumers' taps
5.	Colony counts	No abnormal change	Number/1ml at 22°C	Consumers' taps, service
			Number/1ml at 37°C	Reservoirs and treatment works
6.	Conductivity (i)	2500	μS/cm at 20°C	Supply point*
7.	Hydrogen ion	9.5	pHvalue	Consumers' taps
8.	Sulphate (i)	250	mgSO4 /l	Supply point*
9.	Total indicative dose (for radioactivity) (ii)	0.10	mSv/year	Supply point*
10.	Total organic carbon (TOC)	No abnormal change	mgC/l	Supply point*
11.	Tritium (for radioactivity)	100	Bq/l	Supply point*
12.	Turbidity	1	NTU	Treatment works

Part IV

SCHEDULE 3 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

(1)	(2)	(3)	(4)
Substances and parameters subject to check monitoring	Estimated population of water supply zone	Reduced	Standard
Notes:
* Sampling for these parameters may be within water supply zones or at supply points as specified in Table 3, subject to notes (ii) and (iii) below.
(i) Where the population is not an exact multiple of 5,000, the population figure should be rounded up to the nearest multiple of 5,000.
(ii) Check monitoring in water supply zones is required only where chloramination is practised. In other circumstances audit monitoring is required.
(iii) 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.
(iv) To monitor for total indicative dose (for radioactivity).
E. coli
Coliform bacteria	<100		4
Residual disinfectant	≥100		12 per 5,000 population(i)
Aluminium
Ammonium
Clostridium perfringens (including spores)*	<100	1	2
	100—4,999	2	4
	5,000—9,999	6	12
Colony counts	10,000—29,999	12	24
Colour	30,000—49,999	18	36
Conductivity*	50,000—79,999	26	52
Hydrogen ion	80,000—100,000	38	76
Iron
Manganese
Nitrate(ii)
Nitrite(ii)
Odour
Taste
Turbidity
Parameters subject to audit monitoring
Aluminium
Antimony
Arsenic
Benzene*	<100		1
Benzo(a)pyrene	100—4,999		4
Boron*	5,000—100,000		8
Bromate(iii)
Cadmium
Chromium
Copper
Cyanide*
1,2 dichloroethane*
Enterococci
Fluoride*
Iron
Lead
Manganese
Mercury*
Nickel
Nitrate (ii)
Nitrite (ii)
Pesticides and related products*
Polycyclic aromatic	<100		1
hydrocarbons	100—4,999		4
Selenium	5,000—100,000		8
Sodium
Trichloroethene
/Tetrachloroethene*
Tetrachloromethane*
Trihalomethanes
Chloride*
Sulphate*
Total organic carbon*
Tritium*
Gross alpha* (iv)
Gross beta* (iv)

TABLE 3 ANNUAL SAMPLING FREQUENCIES: TREATMENT WORKS OR SUPPLY POINTS*

(1)	(2)	(3)	(4)	(5)
Item	Substances and parameters	Volume of water supplied m3/d	Reduced	Standard
Notes:
* Sampling is at treatment works for the substances and parameters shown in column (1) of the Table as items 1 to 6 and at supply points for the other substances and parameters, except nitrite, subject to notes (ii) and (iii) below.
(i) Check monitoring is required only in respect of surface waters (see regulation 6(2) and Table 1 in Schedule 3).
(ii) Sampling at treatment works when chloramination is practised.
(ii) Sampling at treatment works when chloramination is not practised.
(iv) 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.
(v) To monitor for total indicative dose (for radioactivity).
1.	E. Coli	<20		4
2.	Coliform bacteria	20—1,999	12	52
3.	Colony counts	2,000—5,999	52	104
4.	Nitrite (ii)	6,000—11,999	104	208
5.	Residual disinfectant	≥12,000	104	365
6.	Turbidity
Subject to check monitoring
7.	Clostridium perfringens(i)	<20		2
		20 — 999	2	4
8.	Conductivity	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
10.	Boron
11.	Bromate (iv)
12.	Cyanide
13.	1,2 dichloroethane
14.	Fluoride
15.	Mercury	<20		1
16.	Nitrite (ii)	20—999		4
17.	Pesticides and Related products	1,000—49,999	8
		50,000—89,999	12
		90,000—299,999	24
		300,000—649,000	36
18.	Trichloroethene ) Tetrachloroethene)	≥650,000	48
19.	Tetrachloromethane
20.	Chloride
21.	Sulphate
22.	Total organic carbon
23.	Tritium
24.	Gross alpha (v)
25.	Gross beta (v)

regulation 16

SCHEDULE 4 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 microorganisms	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 for15 minutes. Allow the medium to cool and add:

D-cycloserine	400.0mg
Polymyxine-B sulphate	25.0mg
Indoxyl-[beta]-D-glucoside	60.0mg
to be dissolved in 8ml sterile water before addition
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)	(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
Notes:
(i) The method of analysis should determine total cyanide in all forms.
(ii) The performance characteristics apply to each individual pesticide and will depend on the pesticide concerned.
(iii) The performance characteristics apply to the individual substances specified at 25% of the parametric value in Part I of Table B in Schedule 1.
(iv) The performance characteristics apply to the individual substances specified at 50% of the parametric value in Part I of Table B in Schedule 1.
(v) The performance characteristics apply to the prescribed value of 4NTU.
(vi) The performance characteristics apply to the specification of 1NTU for water leaving treatment works.
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
Cyanide(i)	10	10	10
1,2-dichloroethane	25	25	10
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 products(ii)	25	25	25
Polycyclic aromatic hydrocarbons(iii)	25	25	25
Selenium	10	10	10
Sodium	10	10	10
Sulphate	10	10	10
Tetrachloromethane	20	20	20
Trichloroethene(iv)	25	25	10
Trihalomethanes: Total(iii)	25	25	10
Turbidity(v)	10	10	10
Turbidity (vi)	25	25	25

regulation 40

SCHEDULE 5 AMENDMENT OF THE WATER SUPPLY (WATER QUALITY) REGULATIONS 1989

The amendments to the 1989 Regulations referred to in regulation 40 are—

(a) after regulation 13, the insertion of the following regulation—

“Frequency of sampling for particular organisms and substances

13A.— (1) Subject to paragraphs (5) and (6), in each of the years 2002 and 2003, a water undertaker shall take, or cause to be taken, from its sampling points or, as the case may be, its supply points, for analysis for testing against the concentrations and values specified in column (2) of Table 4A for the organisms and substances listed in column (1) of that Table, not less than the number of samples specified in paragraphs (2) and (3).

(2) In respect of supply points and the supply of a volume of water within a range shown in column (3) of that Table, the number is that shown in column (4) of that Table with the prefix “S” as applicable to a volume within that range.

(3) In respect of sampling points and the supply of water to an estimated population within a range shown in column (5) of that Table, the number is that shown in column (6) of that Table with the prefix “S” as applicable to a population within that range.

(4) In each of those years samples shall be taken at regular intervals throughout the year.

(5) Where—

(a) a programme of work has been approved or is treated as approved under regulation 41 (transitional provision: programmes of work) of the Water Supply (Water Quality) Regulations 2001; or has otherwise been agreed by the National Assembly for Wales; and

(b) at least one of the steps required to be taken in accordance with that programme—

(i) relates to an organism or substance listed in column (1) of Table 4A; and

(ii) remains to be completed,

the number of samples to be taken in any period of twelve months beginning with the date on which the programe was approved, treated as approved, or agreed (as the case may be) and ending on the day on which the last of those steps is completed, for analysis for testing for that organism or substance, may be the number shown in column (4) or, as the case may be, column (6) of that Table with the prefix “R”.

(6) Where analysis of the samples taken by a water undertaker in 2002 in accordance with this regulation has established a concentration or value in respect of an organism or substance listed in column (1) of Table 4A that is significantly lower than the prescribed concentration or value, the number of samples to be taken in 2003, for analysis for testing for that organism or substance, may be the number shown in column (4) or, as the case may be, column (6) of that Table with the prefix “R”.”;

(b) after regulation 20, the insertion of the following regulation—

“Additional testing for particular parameters

20A.   The samples taken in accordance with regulation 13 shall additionally be tested against the concentrations and values specified in column (2) of Table 4B.”;

(c) in regulation 21 (collection and analysis of samples)—

(i) in paragraph (2), the insertion, after “means”, of “subject to paragraph (3)”; and

(ii) the addition, at the end, of the following—

“(3) In relation to each of the parameters and other substances listed in column (1) of Table 4B, paragraph (2)(d) shall have effect as if for sub-paragraph (iii) there were substituted the requirements of regulation 21A.”

(d) after regulation 21, the insertion of the following regulation—

“Method of analysis of samples for particular parameters, and substances

21A.— (1) The method of analysis used for testing for a parameter or other substance listed in column (1) of Table 4B against the concentrations in column (2) of that Table must be capable, at the time of use—

(a) of measuring concentrations with the trueness and precision specified in relation to that parameter or substance in columns (3) and (4) of Table 4B; and

(b) of detecting the parameter or substance at the limit of detection specified in relation to it in column (5) of that Table.

(2) For the purposes of paragraph (1)—

• “limit of detection” is to be calculated as—

  (a)

  three times the relative within batch standard deviation of a natural sample containing a low concentration of the parameter or substance; or

  (b)

  five times the relative within batch standard deviation of a blank sample;

• “precision” (the random error) is the standard deviation (within a batch and between batches) of the spread of results about the mean; and

• “trueness” (the systematic error) is the difference between the mean value of a large number of repeated measurements and the true value.”;

(e) in regulation 29, in paragraph (1)(f)—

(i) after the words “Part IV of these Regulations”, the insertion of “, other than regulation 13A,”; and

(ii) by the insertion, at the end, of “or regulation 29 of the Water Supply (Water Quality) Regulations 2001”; and

(f) the insertion, after Table 4 in Schedule 3, of the following Tables—

“TABLE 4A SAMPLING FOR PARTICULAR ORGANISMS AND SUBSTANCES

(1)	(2)	(3)	(4)	(5)	(6)
Organism or substance	Concentration or value and unit of measurement	Volume of water supplied m3/d	Annual sampling frequency	Estimated population of water supply zone	Annual sampling frequency
* where the water originates from, or is influenced by, surface waters
Benzene	1.0μg/l
Bromate	1.0μgBrO3/l
		≤999	S2 or R1	≤4,999	S2 or R1
Clostridium perfringens* (Including spores)	0	1,000—49,999	S4 or R1	5,000—50,000	S4 or R1
		≤50,000
	Number/ 100ml		S8 or R2
1,2 dichloroethane	3.0 μg/l
Enterococci	0 Number/100ml
Nitrite	0.10 mgNO2/l

TABLE 4B PARAMETERS AND SUBSTANCES IN RELATION TO WHICH, SUBJECT TO REGULATION 21A, METHODS OF ANALYSIS MUST SATISFY PRESCRIBED CHARACTERISTICS

(1)	(2)	(3)	(4)	(5)
Parameter or other substance	Concentration and unit of measurement	Trueness % of concentration	Precision % of concentration	Limit of detection % of concentration
* Trueness, precision and limit of detection apply to the individual substances specified at 50% of the concentration in column (2).”.
Antimony	5.0 μgSb/l	25	25	25
Arsenic	10 μgAs/l	10	10	10
Benzene	1.0 μg/l	25	25	25
Boron	1.0 mgB/l	10	10	10
Bromate	10 μBrO3/l	25	25	25
Copper	2.0 mgCu/l	10	10	10
1,2 dichloroethane	3.0 μg/l	25	25	10
Lead	25 μgPb/l	10	10	10
Nickel	20 μgNi/l	10	10	10
Nitrite (ex works)	0.1 gNO2/l	10	10	10
Tetrachloroethene*) Trichloroethene* )	10 μg/l	25	25	10

regulation 41

SCHEDULE 6 PROGRAMMES OF WORK

A water undertaker’s programme of work shall—

(a) identify, by reference to the parameters set out in the Table below, those parameters in respect of which the requirements of regulation 41(1)(a) and (b) are unlikely to be satisfied unless steps are taken to secure that those requirements will be met;

(b) identify whether the requirement that the formula [nitrate]/50 + [nitrite]/3 ≤1, where the square brackets signify the concentrations in mg/1 for nitrate (NO₃) and nitrite (NO₂), is unlikely to be satisfied;

(c) specify the steps that the water undertaker intends to take for the purpose of securing that the requirements of regulation 41(1)(a) and (b) are met;

(d) specify the date by which each of the steps specified in accordance with paragraph (c) is proposed to be completed; and

(e) specify the times at which, or the periods within which, reports will be made to the National Assembly for Wales in relation to the taking and completion of the steps specified in accordance with paragraph (c).

TABLE

• Enterococci

• Acrylamide

• Antimony

• Arsenic

• Benzene

• Benzo(a)pyrene

• Boron

• Bromate

• Copper

• 1,2-dichloroethane

• Epichlorohydrin

• Lead

• Nickel

• Nitrite

• Polycyclic aromatic hydrocarbons

• Tetrachloroethene ) sum of concentrations

• Trichloroethene )

• Trihalomethanes — Total (sum of concentrations of chloroform, bromoform, dibromochloromethane and bromodichloromethane)

• Vinyl chloride