The Water Supply (Water Quality) Regulations 2010

Made: 25 March 2010

Laid before Parliament: 30 March 2010

Laid before National Assembly for Wales: 30 March 2010

Coming into force: 20 April 2010

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PART I — General

Title, commencement and application

1

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Interpretation

2

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PART II — Water Supply Zones

Water supply zones

3

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PART III — Wholesomeness

Wholesomeness

4

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PART IV — Monitoring of Water Supplies

Interpretation and application of Part IV

5

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Monitoring: general provisions

6

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Sampling points

7

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Authorisation of supply points

8

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Numbers of samples

9

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Sampling: further provisions

10

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PART V — Monitoring – Additional Provisions

Interpretation of Part V

11

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Sampling for particular substances and parameters

12

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Sampling at treatment works

13

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Sampling at service reservoirs

14

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Sampling: new sources

15

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Collection and analysis of samples

16

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PART VI — Drinking Water Protected Areas

Drinking water abstraction points: monitoring sites

17

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PART VII — Investigations, Authorisation of Departures and Remedial Action

Investigations: Schedule 1 parameters

18

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Investigations: indicator parameters

19

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Action by Welsh Ministers

20

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Failure attributable to domestic distribution system where water is supplied to the public

21

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Authorisation of temporary supply of water that is not wholesome

22

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Authorisations: terms and conditions

23

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Authorisations: other limitations

24

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Publicity for authorisations

25

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Revocation and modification of authorisations

26

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PART VIII — Water Treatment

Disinfection and other treatment arrangements

27

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Risk assessment

28

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Procedure following risk assessment and prohibition of supply

29

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Contamination from pipes

30

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Application and introduction of substances and products

31

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Use of processes

32

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Offences

33

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PART IX — Records and Information

Maintenance of records

34

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Provision of information

35

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PART X — Functions of Local Authorities in Relation to Water Quality

Application and interpretation

36

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Duties of local authorities: supplementary provision

37

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PART XI — Enforcement

Contraventions by relevant suppliers

38

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PART XII — Revocation of Regulations

Revocation of Regulations

39

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SCHEDULE 1 — PRESCRIBED CONCENTRATIONS AND VALUES

¹ Note: Compliance required as to 95% of samples from each service reservoir (regulation 4(6)).	¹ Note: Compliance required as to 95% of samples from each service reservoir (regulation 4(6)).	¹ Note: Compliance required as to 95% of samples from each service reservoir (regulation 4(6)).	¹ Note: Compliance required as to 95% of samples from each service reservoir (regulation 4(6)).	¹ Note: Compliance required as to 95% of samples from each service reservoir (regulation 4(6)).
Part I: Directive requirements	Part I: Directive requirements	Part I: Directive requirements	Part I: Directive requirements	Part I: Directive requirements
Item	Parameters	Concentration or Value (maximum)	Units of Measurement	Point of compliance
1	Enterococci	0	number/100 ml	Consumers' taps
2	Escherichia coli (E coli)	0	number/100 ml	Consumers' taps
Part II: National requirements	Part II: National requirements	Part II: National requirements	Part II: National requirements	Part II: National requirements
Item	Parameters	Concentration or Value (maximum)	Units of Measurement	Point of compliance
1	Coliform bacteria	0	number/100 ml	Service reservoirs¹ and water treatment works
2	Escherichia coli (E coli)	0	number/100 ml	Service reservoirs and water treatment works
Part I: National requirements
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Item	Parameters	Concentration or Value (maximum)	Units of Measurement	Point of compliance
Notes:	Notes:	Notes:	Notes:	Notes:
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.	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.	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.	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.	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.
See also regulation 6(6).	See also regulation 6(6).	See also regulation 6(6).	See also regulation 6(6).	See also regulation 6(6).
See also regulation 4(2)(d).	See also regulation 4(2)(d).	See also regulation 4(2)(d).	See also regulation 4(2)(d).	See also regulation 4(2)(d).
See the definition of “pesticides and related products” in regulation 2.	See the definition of “pesticides and related products” in regulation 2.	See the definition of “pesticides and related products” in regulation 2.	See the definition of “pesticides and related products” in regulation 2.	See the definition of “pesticides and related products” in regulation 2.
The parametric value applies to each individual pesticide.	The parametric value applies to each individual pesticide.	The parametric value applies to each individual pesticide.	The parametric value applies to each individual pesticide.	The parametric value applies to each individual pesticide.
“Pesticides: Total” means the sum of the concentrations of the individual pesticides detected and quantified in the monitoring procedure.	“Pesticides: Total” means the sum of the concentrations of the individual pesticides detected and quantified in the monitoring procedure.	“Pesticides: Total” means the sum of the concentrations of the individual pesticides detected and quantified in the monitoring procedure.	“Pesticides: Total” means the sum of the concentrations of the individual pesticides detected and quantified in the monitoring procedure.	“Pesticides: Total” means the sum of the concentrations of the individual pesticides detected and quantified in the monitoring procedure.
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.	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.	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.	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.	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.
The parametric value applies to the sum of the concentrations of the individual compounds detected and quantified in the monitoring process.	The parametric value applies to the sum of the concentrations of the individual compounds detected and quantified in the monitoring process.	The parametric value applies to the sum of the concentrations of the individual compounds detected and quantified in the monitoring process.	The parametric value applies to the sum of the concentrations of the individual compounds detected and quantified in the monitoring process.	The parametric value applies to the sum of the concentrations of the individual compounds detected and quantified in the monitoring process.
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.	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.	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.	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.	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	[^f01001]
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 [^f01002]	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	[^f01001]
14	Fluoride	1.5	mgF/l	Consumers' taps
15	Lead [^f01002]	a 25, from 25th December 2003 until immediately before 25th December 2013	μgPb/l	Consumers' taps
15	Lead [^f01002]	b 10, on and after 25th December 2013	μgPb/l	Consumers' taps
16	Mercury	1.0	μgHg/l	Consumers' taps
17	Nickel [^f01002]	20	μgNi/l	Consumers' taps
18	Nitrate [^f01003]	50	mgNO₃/l	Consumers' taps
19	Nitrite [^f01003]	0.50	mgNO₂/l	Consumers' taps
19	Nitrite [^f01003]	0.10		Treatment Works
20	Pesticides [^f01004][^f01005]
20	Aldrin)	0.030	μg/l	Consumer’s taps
20	Dieldrin)	0.030	μg/l	Consumer’s taps
20	Heptachlor)	0.030	μg/l	Consumer’s taps
20	Heptachlor	0.030	μg/l	Consumer’s taps
20	epoxide)	0.030	μg/l	Consumer’s taps
20	other pesticides	0.10	μg/l	Consumers' taps
21	Pesticides: Total [^f01006]	0.50	μg/l	Consumers' taps
22	Polycyclic aromatic hydrocarbons [^f01007]	0.10	μg/l	Consumers' taps
23	Selenium	10	μgSe/l	Consumers' taps
24	Tetrachloroethene and Trichloroethene [^f01008]	10	μg/l	Consumers' taps
25	Trihalomethanes: Total [^f01009]	100	μg/l	Consumers' taps
26	Vinyl chloride	0.50	μg/l	[^f01001]
Part II: National requirements	Part II: National requirements	Part II: National requirements	Part II: National requirements	Part II: National requirements
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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

SCHEDULE 2 — INDICATOR PARAMETERS

Notes:	Notes:	Notes:	Notes:	Notes:
¹ The water should not be aggressive.	¹ The water should not be aggressive.	¹ The water should not be aggressive.	¹ The water should not be aggressive.	¹ The water should not be aggressive.
2 . . .	2 . . .	2 . . .	2 . . .	2 . . .
³ May be monitored from samples of water leaving treatment works or other supply point, as no significant change during distribution.	³ May be monitored from samples of water leaving treatment works or other supply point, as no significant change during distribution.	³ May be monitored from samples of water leaving treatment works or other supply point, as no significant change during distribution.	³ May be monitored from samples of water leaving treatment works or other supply point, as no significant change during distribution.	³ May be monitored from samples of water leaving treatment works or other supply point, as no significant change during distribution.
Item	Parameters	Specification Concentration or Value (maximum unless otherwise stated) or State	Units of Measurement	Point of compliance
1	Ammonium	0.50	mgNH4/l	Consumers' taps
2	Chloride ¹	250	mgCl/l	Supply point³
3	Clostridium perfringens (including spores)	0	Number/100 ml	Supply point³
4	Coliform bacteria	0	Number/100 ml	Consumers' taps
5	Colony counts	No abnormal change	Number/1 ml at 22°C	Consumers' taps, service
5	Colony counts	No abnormal change	Number/1 ml at 37°C	Reservoirs and treatment works
6	Conductivity ¹	2500	μS/cm at 20°C	Supply point³
7	Hydrogen ion	9.5	pHvalue	Consumers' taps
7	Hydrogen ion	6.5 (minimum)	pH value
8	Sulphate ¹	250	mgSO4/l	Supply point³
9	. . .	. . .	. . .	. . .
10	Total organic carbon (TOC)	No abnormal change	mgC/l	Supply point³
11	. . .	. . .	. . .	. . .
12	Turbidity	1	NTU	Treatment works

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
Subject to check monitoring
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.	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.	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.	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.
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.	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.	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.	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.
Check monitoring in water supply zones is required only where chloramination is practised. In other circumstances audit monitoring is required.	Check monitoring in water supply zones is required only where chloramination is practised. In other circumstances audit monitoring is required.	Check monitoring in water supply zones is required only where chloramination is practised. In other circumstances audit monitoring is required.	Check monitoring in water supply zones is required only where chloramination is practised. In other circumstances audit monitoring is required.
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.	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.	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.	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.
To monitor for total indicative dose (for radioactivity).	To monitor for total indicative dose (for radioactivity).	To monitor for total indicative dose (for radioactivity).	To monitor for total indicative dose (for radioactivity).
E coli	<100		4
Coliform bacteria	≥100		12 per 5,000 population[^f01013]
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	<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
Clostridium perfringens (including spores)[^f01014]	<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
Colony counts	<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
Colour	<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
Conductivity[^f01014]	<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
Hydrogen ion	<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
Iron	<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
Manganese	<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
Nitrate [^f01015]	<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
Nitrite [^f01015]	<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
Odour	<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
Taste	<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
Turbidity	<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
Subject to audit monitoring	Subject to audit monitoring	Subject to audit monitoring	Subject to audit monitoring
Aluminium	<100 100—4,999 5,000—100,000		1 4 8
Antimony	<100 100—4,999 5,000—100,000		1 4 8
Arsenic	<100 100—4,999 5,000—100,000		1 4 8
Benzene[^f01014]	<100 100—4,999 5,000—100,000		1 4 8
Benzo(a)pyrene	<100 100—4,999 5,000—100,000		1 4 8
Boron[^f01014]	<100 100—4,999 5,000—100,000		1 4 8
Bromate [^f01016]	<100 100—4,999 5,000—100,000		1 4 8
Cadmium	<100 100—4,999 5,000—100,000		1 4 8
Chromium	<100 100—4,999 5,000—100,000		1 4 8
Clostridium perfringens (including spores)	<100 100—4,999 5,000—100,000		1 4 8
Copper	<100 100—4,999 5,000—100,000		1 4 8
Cyanide[^f01014]	<100 100—4,999 5,000—100,000		1 4 8
1,2 dichloroethane[^f01014]	<100 100—4,999 5,000—100,000		1 4 8
Enterococci	<100 100—4,999 5,000—100,000		1 4 8
Fluoride[^f01014]	<100 100—4,999 5,000—100,000		1 4 8
Iron	<100 100—4,999 5,000—100,000		1 4 8
Lead	<100 100—4,999 5,000—100,000		1 4 8
Manganese	<100 100—4,999 5,000—100,000		1 4 8
Mercury[^f01014]	<100 100—4,999 5,000—100,000		1 4 8
Nickel	<100 100—4,999 5,000—100,000		1 4 8
Nitrate [^f01015]	<100 100—4,999 5,000—100,000		1 4 8
Nitrite [^f01015]	<100 100—4,999 5,000—100,000		1 4 8
Pesticides and related products [^f01014]	<100 100—4,999 5,000—100,000		1 4 8
Polycyclic aromatic hydrocarbons	<100 100—4,999 5,000—100,000		1 4 8
Selenium	<100 100—4,999 5,000—100,000		1 4 8
Sodium	<100 100—4,999 5,000—100,000		1 4 8
Trichloroethene /Tetrachloroethene[^f01014]	<100 100—4,999 5,000—100,000		1 4 8
Tetrachloromethane[^f01014]	<100 100—4,999 5,000—100,000		1 4 8
Trihalomethanes	<100 100—4,999 5,000—100,000		1 4 8
Chloride[^f01014]	<100 100—4,999 5,000—100,000		1 4 8
Sulphate[^f01014]	<100 100—4,999 5,000—100,000		1 4 8
Total organic carbon[^f01014]	<100 100—4,999 5,000—100,000		1 4 8
Tritium[^f01014]	<100 100—4,999 5,000—100,000		1 4 8
Gross alpha [^f01014] [^f01017]	<100 100—4,999 5,000—100,000		1 4 8
Gross beta [^f01014] [^f01017]	<100 100—4,999 5,000—100,000		1 4 8

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
Sampling at treatment works when chloramination is practised.	Sampling at treatment works when chloramination is practised.	Sampling at treatment works when chloramination is practised.	Sampling at treatment works when chloramination is practised.	Sampling at treatment works when chloramination is practised.
Check monitoring is required only in respect of surface waters (see regulation 6(2) and Table 1 in Schedule 3).	Check monitoring is required only in respect of surface waters (see regulation 6(2) and Table 1 in Schedule 3).	Check monitoring is required only in respect of surface waters (see regulation 6(2) and Table 1 in Schedule 3).	Check monitoring is required only in respect of surface waters (see regulation 6(2) and Table 1 in Schedule 3).	Check monitoring is required only in respect of surface waters (see regulation 6(2) and Table 1 in Schedule 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.	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.	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.	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.	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.
Sampling at treatment works when chloramination is not practised.	Sampling at treatment works when chloramination is not practised.	Sampling at treatment works when chloramination is not practised.	Sampling at treatment works when chloramination is not practised.	Sampling at treatment works when chloramination is not practised.
To monitor for total indicative dose (for radioactivity).	To monitor for total indicative dose (for radioactivity).	To monitor for total indicative dose (for radioactivity).	To monitor for total indicative dose (for radioactivity).	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	<20 20—1,999 2,000—5,999 6,000—11,999 ≥12,000	— 12 52 104 104	4 52 104 208 365
3.	Colony counts	<20 20—1,999 2,000—5,999 6,000—11,999 ≥12,000	— 12 52 104 104	4 52 104 208 365
4.	Nitrite [^f01018]	<20 20—1,999 2,000—5,999 6,000—11,999 ≥12,000	— 12 52 104 104	4 52 104 208 365
5.	Residual disinfectant	<20 20—1,999 2,000—5,999 6,000—11,999 ≥12,000	— 12 52 104 104	4 52 104 208 365
6.	Turbidity	<20 20—1,999 2,000—5,999 6,000—11,999 ≥12,000	— 12 52 104 104	4 52 104 208 365
Subject to check monitoring	Subject to check monitoring	Subject to check monitoring	Subject to check monitoring	Subject to check monitoring
7.	Clostridium perfringens [^f01019]	<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	<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
Subject to audit monitoring	Subject to audit monitoring	Subject to audit monitoring	Subject to audit monitoring	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	<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
11.	Bromate [^f01020]	<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
11A.	Clostridium perfringens (including spores)	<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
12.	Cyanide	<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
13.	1,2 dichloroethane	<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
14.	Fluoride	<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
15.	Mercury	<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
16.	Nitrite [^f01021]	<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
17.	Pesticides and Related products	<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
18.	Trichloroethene	<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
18.	Tetrachloroethene	<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
19.	Tetrachloromethane	<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
20.	Chloride	<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
21.	Sulphate	<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
22.	Total organic carbon	<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
23.	Tritium	<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
24.	Gross alpha [^f01022]	<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
25.	Gross beta [^f01022]	<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

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 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

Notes:	Notes:	Notes:	Notes:
¹ The method of analysis should determine total cyanide in all forms.	¹ The method of analysis should determine total cyanide in all forms.	¹ The method of analysis should determine total cyanide in all forms.	¹ The method of analysis should determine total cyanide in all forms.
² The performance characteristics apply to each individual pesticide and will depend on the pesticide concerned.	² The performance characteristics apply to each individual pesticide and will depend on the pesticide concerned.	² The performance characteristics apply to each individual pesticide and will depend on the pesticide concerned.	² The performance characteristics apply to each individual pesticide and will depend 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.	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.	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.	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.	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.	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.	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 4NTU.	⁵ The performance characteristics apply to the prescribed value of 4NTU.	⁵ The performance characteristics apply to the prescribed value of 4NTU.	⁵ The performance characteristics apply to the prescribed value of 4NTU.
⁶ The performance characteristics apply to the specification of 1NTU for water leaving treatment works.	⁶ The performance characteristics apply to the specification of 1NTU for water leaving treatment works.	⁶ The performance characteristics apply to the specification of 1NTU for water leaving treatment works.	⁶ The performance characteristics apply to the specification of 1NTU 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
Cyanide ¹	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 ²	25	25	25
Polycyclic aromatic hydrocarbons ³	25	25	25
Selenium	10	10	10
Sodium	10	10	10
Sulphate	10	10	10
Tetrachloromethane	20	20	20
Trichloroethene ⁴	25	25	10
Trihalomethanes: Total ³	25	25	10
Turbidity ⁵	10	10	10
Turbidity ⁶	25	25	25

Signed

Jane Davidson — Minister for Environment, Sustainability and Housing, one of the Welsh Ministers — 2010-03-25

Explanatory note

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Footnotes

[^f00001]: S.1. 2004/3328, as amended by S.I. 2005/850; the powers conferred on the National Assembly for Wales by those instruments are now exercisable by the Welsh Ministers by virtue of section 162 of, and paragraph 30 of Schedule 11 to, the Government of Wales Act 2006 (c. 32).

[^f00002]: 1972 c. 68.

[^f00003]: OJ No L 40, 11.02.1989, p.12, as amended.

[^f00004]: OJ No L 204, 21.07.1998, p.37, as amended.

[^f00005]: 1991 c. 56; the functions of the Secretary of State under section 67 were transferred to the National Assembly for Wales (“the Assembly”) – (a) for the making of regulations concerning water supplied using the supply system of a water undertaker, in relation to the supply system of any water undertaker whose area is wholly or mainly in Wales and (b) for the making of regulations concerning water supplied other than using the supply system of a water undertaker, in relation to Wales, by article 2 of, and Schedule 1 to, the National Assembly for Wales (Transfer of Functions) Order 1999 (S.I. 1999/672) (“the Order”); the functions of the Secretary of State under section 69 of that Act were, in relation to any water undertaker whose area is wholly or mainly in Wales and any licensed water supplier so far as relating to licensed activities using the supply system of any such water undertaker, transferred to the Assembly by the same provisions of the Order; the functions of the Secretary of State under section 77 of that Act were transferred to the Assembly in relation to Wales by the same provision of the Order; the functions of the Secretary of State under section 213 of that Act were made exercisable by the Assembly to the same extent as the powers to which that section applies were made exercisable by the Assembly by virtue of the same provisions of the Order: see the entry in Schedule 1 to the Order for the Water Industry Act 1991 as substituted by paragraph (e) of Schedule 3 to the National Assembly for Wales (Transfer of Functions) Order 2000 (S.I. 2000/253) and amended by section 100(2) of the Water Act 2003 (c. 37); there are other amending instruments but none are relevant. Section 69 of that Act was amended by sections 58 and 101(1) of, and paragraphs 2, 19 and 49 of Schedule 8 to, the Water Act 2003. Section 213 of that Act was amended by sections 58 and 101(1) of paragraph 39 of Schedule 7 to, and paragraphs 2, 19 and 49 of Schedule 8 to the Water Act 2003 and by section 52 and 56(6) and paragraph 28 of Schedule 1 to the Competition of Services (Utilities Act) 1992. References in Schedule 1 to the Order to specific sections and to the Water Industry Act 1991 generally are treated by section 100(6) of the Water Act 2003 as referring to that Act, as amended by the Water Act 2003. See section 219(4A) of the Water Industry Act 1991 as inserted by section 101(1) of, and paragraphs 2 and 50 of Schedule 8 to, the Water Act 2003 for the definition of “supply system”. See section 219(1) of the Water Industry Act 1991 as amended by section 101(1) of, and paragraphs 2 and 50 of Schedule 8 to, the Water Act 2003 for the definition of “licensed water supplier”. By virtue of section 162 of, and paragraph 30 of Schedule 11 to, the Government of Wales Act 2006 (c. 32), the functions transferred to and made exercisable by the Assembly are now exercisable by the Welsh Ministers.

[^f00006]: 1991 c. 56.

[^f00007]: 1996 c. 56.

[^f00008]: S.I.2010/66 (W.16) as amended by S.I. 2010/147 (W.22).

[^f00009]: S.I 2001/3911 (W.323), as amended by S.I. 2005/2035.

[^f00010]: S.I. 2007/3374 (W.299).

Editorial notes

[^key-a960f0cb3875ab2b0b26bcfdb135ded1]: Regulations revoked (15.6.2018) by The Water Supply (Water Quality) Regulations 2018 (S.I. 2018/647), reg. 1(1), Sch. 6 (with reg. 39)

Monitoring: radioactive substances

6A

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Sampling points

Authorisation of supply points

Numbers of samples

Sampling: further provisions

SCHEDULENonBreakingSpace2A — Radioactive substances parameters

Parameters	Maximum concentration or value	Maximum concentration or value	Units of measurement
(i)Enforcement action by the Welsh Ministers is deemed justified on radiological protection grounds without further consideration where radon concentrations exceed 1,000 Bq/1.	(i)Enforcement action by the Welsh Ministers is deemed justified on radiological protection grounds without further consideration where radon concentrations exceed 1,000 Bq/1.	(i)Enforcement action by the Welsh Ministers is deemed justified on radiological protection grounds without further consideration where radon concentrations exceed 1,000 Bq/1.	(i)Enforcement action by the Welsh Ministers is deemed justified on radiological protection grounds without further consideration where radon concentrations exceed 1,000 Bq/1.
(ii)If tritium concentration exceeds its parametric value, an investigation (which may include analysis) of the presence of artificial radionuclides must be carried out.	(ii)If tritium concentration exceeds its parametric value, an investigation (which may include analysis) of the presence of artificial radionuclides must be carried out.	(ii)If tritium concentration exceeds its parametric value, an investigation (which may include analysis) of the presence of artificial radionuclides must be carried out.	(ii)If tritium concentration exceeds its parametric value, an investigation (which may include analysis) of the presence of artificial radionuclides must be carried out.
Indicative dose (for radioactivity)	0,10	0,10	mSv
Radon	100	100	Bq/1
Tritium (for radioactivity)	Tritium (for radioactivity)	100	Bq/l

SCHEDULENonBreakingSpace3A — Monitoring of radioactive substances

Radon

1

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Tritium

2

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Indicative Dose

3

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Water treatment

4

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Averaging

5

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

SCHEDULENonBreakingSpace5 — Monitoring for indicative dose and analytical performance characteristics

Monitoring for compliance with the indicative dose

1

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Screening for certain radionuclides, or screening for an individual radionuclide

3

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Screening strategies for gross alpha activity and gross beta activity

5

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

6

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

7

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

8

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Calculation of the indicative dose

9

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

10

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Performance characteristics and methods of analysis

11

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .