The Water Supply (Water Quality) Regulations 2010

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
Note: a Note: Compliance required as to 95% of samples from each service reservoir (regulation 4(6)).
1	Enterococci	0	number/100 ml	Consumers' taps
2	Escherichia coli (E coli)	0	number/100 ml	Consumers' taps
Part II: National requirements
Item	Parameters	Concentration or Value (maximum)	Units of Measurement	Point of compliance
1	Coliform bacteria	0	number/100 ml	Service reservoirsa and water treatment works
2	Escherichia coli (E coli)	0	number/100 ml	Service reservoirs and water treatment works

Table B

Chemical Parameters

Part I: National requirements
Item	Parameters	Concentration or Value (maximum)	Units of Measurement	Point of compliance
Notes:
a 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.
b See also regulation 6(6).
c See also regulation 4(2)(d).
d See the definition of “pesticides and related products” in regulation 2.
e The parametric value applies to each individual pesticide.
f “Pesticides: Total” means the sum of the concentrations of the individual pesticides detected and quantified in the monitoring procedure.
g 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.
h The parametric value applies to the sum of the concentrations of the individual compounds detected and quantified in the monitoring process.
i 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	a
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	μBrO3/l	Consumers' taps
8	Cadmium	5.0	μgCd/l	Consumers' taps
9	Chromium	50	μgCr/l	Consumers' taps
10	Copper b	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	a
14	Fluoride	1.5	mgF/l	Consumers' taps
15	Lead b	(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 b	20	μgNi/l	Consumers' taps
18	Nitrate c	50	mgNO3/l	Consumers' taps
19	Nitrite c	0.50	mgNO2/l	Consumers' taps
		0.10		Treatment Works
20	Pesticides de
	Aldrin)	0.030	μg/l	Consumer’s taps
	Dieldrin)
	Heptachlor)
	Heptachlor
	epoxide)
	other pesticides	0.10	μg/l	Consumers' taps
21	Pesticides: Total f	0.50	μg/l	Consumers' taps
22	Polycyclic aromatic hydrocarbons g	0.10	μg/l	Consumers' taps
23	Selenium	10	μgSe/l	Consumers' taps
24	Tetrachloroethene and Trichloroethene h	10	μg/l	Consumers' taps
25	Trihalomethanes: Total i	100	μg/l	Consumers' taps
26	Vinyl chloride	0.50	μg/l	a

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	Iron	200	μgFe/l	Consumers' taps
4	Manganese	50	μgMn/l	Consumers' taps
5	Odour	Acceptable to consumers and no abnormal change	... ... ... ...	Consumers' taps
6	Sodium	200	mgNa/l	Consumers' taps
7	Taste	Acceptable to consumers and no abnormal change	... ... ... ...	Consumers' taps
8	Tetrachlorome-thane	3	μg/l	Consumers' taps
9	Turbidity	4	NTU	Consumers' taps

Regulations 2 and 4

SCHEDULE 2 INDICATOR PARAMETERS

Item	Parameters	Specification Concentration or Value (maximum unless otherwise stated) or State	Units of Measurement	Point of compliance
Notes:
a The water should not be aggressive.
b Excluding tritium, potassium-40, radon and radon decay products.
c 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 a	250	mgCl/l	Supply pointc
3	Clostridium perfringens (including spores)	0	Number/100 ml	Supply pointc
4	Coliform bacteria	0	Number/100 ml	Consumers' taps
5	Colony counts	No abnormal change	Number/1 ml at 22°C	Consumers' taps, service
			Number/1 ml at 37°C	Reservoirs and treatment works
6	Conductivity a	2500	μS/cm at 20°C	Supply pointc
7	Hydrogen ion	9.5	pHvalue	Consumers' taps
		6.5 (minimum)	pH value
8	Sulphate a	250	mgSO4/l	Supply pointc
9	Total indicative dose (for radioactivity) b	0.10	mSv/year	Supply pointc
10	Total organic carbon (TOC)	No abnormal change	mgC/l	Supply pointc
11	Tritium (for radioactivity)	100	Bq/l	Supply pointc
12	Turbidity	1	NTU	Treatment works

SCHEDULE 3 MONITORING

PART IV

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

Regulation 9

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)	(2)	(3)	(4)
Substances and parameters subject to check monitoring	Estimated population of water supply zone	Reduced	Standard
Subject to check monitoring
a 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.
b Sampling for these parameters may be within water supply zones or at supply points as specified in Table 3, subject to notes (iii) and (iv) below.
c Check monitoring in water supply zones is required only where chloramination is practised. In other circumstances audit monitoring is required.
d 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.
e To monitor for total indicative dose (for radioactivity).
E coli	<100		4
Coliform bacteria	≥100		12 per 5,000 populationa
Residual disinfectant
Aluminium	<100 100—4,999 5,000—9,999 10,000—29,999 30,000—49,999 50,000—79,999 80,000—100,000	1 2 6 12 18 26 38	2 4 12 24 36 52 76
Ammonium
Clostridium perfringens (including spores)b
Colony counts
Colour
Conductivityb
Hydrogen ion
Iron
Manganese
Nitrate c
Nitrite c
Odour
Taste
Turbidity
Subject to audit monitoring
Aluminium	<100 100—4,999 5,000—100,000		1 4 8
Antimony
Arsenic
Benzeneb
Benzo(a)pyrene
Boronb
Bromate d
Cadmium
Chromium
Clostridium perfringens (including spores)
Copper
Cyanideb
1,2 dichloroethaneb
Enterococci
Fluorideb
Iron
Lead
Manganese
Mercuryb
Nickel
Nitrate c
Nitrite c
Pesticides and related products b
Polycyclic aromatic hydrocarbons
Selenium
Sodium
Trichloroethene /Tetrachloroetheneb
Tetrachloromethaneb
Trihalomethanes
Chlorideb
Sulphateb
Total organic carbonb
Tritiumb
Gross alpha b e
Gross beta b e

Regulation 9

Table 3 Annual Sampling Frequencies: Treatment Works or Supply Points

Note 1: 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 nitrate subject to footnotes (ii) and (ii)(a) 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)	(2)	(3)	(4)	(5)
Item	Substances and parameters	Volume of water supplied m3/d	Reduced	Standard
a Sampling at treatment works when chloramination is practised.
b Check monitoring is required only in respect of surface waters (see regulation 6(2) and Table 1 in Schedule 3).
c 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.
d Sampling at treatment works when chloramination is not practised.
e To monitor for total indicative dose (for radioactivity).
1.	E Coli	<20 20—1,999 2,000—5,999 6,000—11,999 ≥12,000	— 12 52 104 104	4 52 104 208 365
2.	Calliform bacteria
3.	Colony counts
4.	Nitrite a
5.	Residual disinfectant
6.	Turbidity
Subject to check monitoring
7.	Clostridium perfringens b	<20 20—999 1,000—1,999 2,000—5,999 6,000—9,999 10,000—15,999 16,000—32,999 33,000—49,999 50,000—67,999 68,000—84,999 85,000—101,999 102,000—119,999 120,000—241,999 242,000—484,999 485,000—728,999	— 2 6 12 18 26 52 78 104 130 156 183 365 730 1,095	2 4 12 24 36 52 104 156 208 260 312 365 730 1,460 2,190
8.	Conductivity
Subject to audit monitoring
9.	Benzene	<20 20—999 1,000—49,999 50,000—89,999 90,000—299,999 300,000—649,000 ≥650,000	1 4 8 12 24 36 48
10.	Boron
11.	Bromate c
11A.	Clostridium perfringens (including spores)
12.	Cyanide
13.	1,2 dichloroethane
14.	Fluoride
15.	Mercury
16.	Nitrite d
17.	Pesticides and Related products
18.	Trichloroethene
	Tetrachloroethene
19.	Tetrachloromethane
20.	Chloride
21.	Sulphate
22.	Total organic carbon
23.	Tritium
24.	Gross alpha e
25.	Gross beta e

Regulation 16

SCHEDULE 4 ANALYTICAL METHODOLOGY

Regulation 16

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 for 15 minutes. Allow the medium to cool and add:
D-cycloserine	400.0mg
Polymyxine-B sulphate	25.0mg
Indoxyl-[beta]-D-glucoside to be dissolved in 8 ml sterile water before addition	60.0mg
Filter-sterilised 0.5% phenolphthalein diphosphate solution	20.0 ml
Filter-sterilised 4.5% FeCl3·6H2O	2.0 ml

Table A2 Parameters for which, Subject to Regulation 16(7), Methods of Analysis are Prescribed

(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:
a The method of analysis should determine total cyanide in all forms.
b The performance characteristics apply to each individual pesticide and will depend on the pesticide concerned.
c The performance characteristics apply to the individual substances specified at 25% of the parametric value in Part I of Table B in Schedule 1.
d The performance characteristics apply to the individual substances specified at 50% of the parametric value in Part I of Table B in Schedule 1.
e The performance characteristics apply to the prescribed value of 4NTU.
f 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 a	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 b	25	25	25
Polycyclic aromatic hydrocarbons c	25	25	25
Selenium	10	10	10
Sodium	10	10	10
Sulphate	10	10	10
Tetrachloromethane	20	20	20
Trichloroethene d	25	25	10
Trihalomethanes: Total c	25	25	10
Turbidity e	10	10	10
Turbidity f	25	25	25