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The Water Supply (Water Quality) Regulations 2000

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regulations 2 and 4

SCHEDULE 1PRESCRIBED CONCENTRATIONS AND VALUES

TABLE A

MICROBIOLOGICAL PARAMETERS

Part I: Directive requirements
ItemParametersConcentration or Value maximum)Units of MeasurementPoint of compliance
1.Enterococci0number/100mlConsumers' taps
2.Escherichia coli (E. coli)0number/100mlConsumers' taps
Part II: National requirements
ItemParametersConcentration or Value maximum)Units of MeasurementPoint of compliance
Note:
*

Compliance required as to 95% of samples from each service reservoir (regulation 4(6)).

1.Coliform bacteria0number/100mlService reservoirs* and water treatment works
2.Escherichia coli (E. coli)0number/100mlService reservoirs and water treatment works

TABLE B

CHEMICAL PARAMETERS

Part I: Directive requirements
ItemParametersConcentration or Value maximum)Units of MeasurementPoint 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.Acrylamide0.10μg/l(i)
2.Antimony5.0μgSb/lConsumers' taps
3.Arsenic10μgAs/lConsumers' taps
4.Benzene1.0μg/lConsumers' taps
5.Benzo(a)pyrene0.010μg/lConsumers' taps
6.Boron1.0mgB/lConsumers' taps
7.Bromate10μgBrO3/lConsumers' taps
8.Cadmium5.0μgCd/lConsumers' taps
9.Chromium50μgCr/lConsumers' taps
10.Copper(ii)2.0mgCu/lConsumers' taps
11.Cyanide50μgCN/lConsumers' taps
12.1, 2 dichloroethane3.0μg/lConsumers' taps
13.Epichlorohydrin0.10μg/l(i)
14.Fluoride1.5mgF/lConsumers' taps
15.Lead (ii)(a) 25, from 25th December 2003 until immediately before 25th December 2013μgPb/lConsumers' taps
(b) 10, on and after 25th December 2013μgPb/lConsumers' taps
16.Mercury1.0μgHg/lConsumers' taps
17.Nickel (ii)20μgNi/lConsumers' taps
18.Nitrate (iii)50mgNO3/lConsumers' taps
19.Nitrite (iii)0.50mgNO2/lConsumers' taps
0.10Treatment works
20.Pesticides (iv)(v)
Aldrin0.030μg/lConsumers' taps
Dieldrin
Heptachlor
Heptachlor epoxide
other pesticides0.10μg/lConsumers' taps
21.Pesticides: Total (vi)0.50μg/lConsumers' taps
22.Polycyclic aromatic hydrocarbons (vii)0.10μg/lConsumers' taps
23.Selenium10μgSe/lConsumers' taps
24.Tetrachloroethene and Trichloroethene (viii)10μg/lConsumers' taps
25.Trihalomethanes: Total (ix)100μg/lConsumers' taps
26.Vinyl chloride0.50μg/l(i)
Part II: National requirements
ItemParametersConcentration or Value (maximum unless otherwise stated)Units of MeasurementPoint of compliance
1.Aluminium200μgAl/lConsumers' taps
2.Colour20mg/l Pt/CoConsumers' taps
3.Hydrogen ion10.0pH valueConsumers' taps
6.5 (minimum)pH value
4.Iron200μgFe/lConsumers' taps
5.Manganese50μgMn/lConsumers' taps
6.Odour3 at 25°CDilution numberConsumers' taps
7.Sodium200mgNa/lConsumers' taps
8.Taste3 at 25°CDilution numberConsumers' taps
9.Tetrachloromethane3μg/lConsumers' taps
10.Turbidity4NTUConsumers' taps

regulations 2 and 4

SCHEDULE 2INDICATOR PARAMETERS

ItemParametersSpecification Concentration or Value (maximum) or StateUnits of MeasurementPoint 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.Ammonium0.50mgNH4/lConsumers' taps
2.Chloride (i)250mgCl/lSupply point*
3.Clostridium perfringens (including spores)0Number/100mlSupply point*
4.Coliform bacteria0Number/100mlConsumers' taps
5.Colony countsNo abnormal changeNumber/1ml at 22°CConsumers' taps, service reservoirs and treatment works
5.Colony countsNo abnormal changeNumber/1ml at 37°CConsumers' taps, service reservoirs and treatment works
6.Conductivity (i)2500μS/cm at 20°CSupply point*
7.Sulphate (i)250mgSO4/lSupply point*
8.Total indicative dose (for radioactivity) (ii)0.10mSv/yearSupply point*
9.Total organic carbon (TOC)No abnormal changemgC/lSupply point*
10.Tritium (for radioactivity)100Bq/lSupply point*
11.Turbidity1NTUTreatment works

Part IV

SCHEDULE 3MONITORING

TABLE 1

PARAMETERS AND CIRCUMSTANCES FOR CHECK MONITORING

(1)(2)(3)
ItemParameterCircumstances
1.AluminiumWhen 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.Colour
6.Conductivity
7.Escherichia coli (E. coli)
8.Hydrogen ion concentration
9.IronWhen used as flocculant or where the water originates from, or is influenced by, surface waters
10.ManganeseWhere the water originates from, or is influenced by, surface waters
11.NitrateWhen chloramination is practised
12.NitriteWhen chloramination is practised
13.Odour
14.Taste
15.Turbidity

TABLE 2

ANNUAL SAMPLING FREQUENCIES: WATER SUPPLY ZONES

(1)(2)(3)(4)
Substances and parameters subject to check monitoringEstimated population of water supply zoneReducedStandard
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<1004
Coliform bacteria Residual disinfectant>–10012 per 5,000 population (i)
Aluminium
Ammonium
Clostridium perfringens
Colony counts<10012
Colour100–4,99924
Conductivity*5,000–9,999612
Hydrogen ion10,000–29,9991224
Iron30,000–49,9991836
Manganese50,000–79,9992652
Nitrate (ii)80,000–99,9993876
Nitrite (ii)
Odour
Taste
Turbidity
Parameters subject to audit monitoring
Aluminium
Antimony
Arsenic
Benzene*<1001
Benzo(a)pyrene100–4,9994
Boron*5,000–99,9998
Bromate (iii)
Cadmium
Chromium
Copper
Cyanide*
1,2 dichloroethane*
Enterococci
Fluoride*
Iron
Lead
Manganese
Mercury*
Nickel
Nitrate (ii)
Nitrite (ii)
Pesticides and related products*<1001
100–4,9994
Polycyclic aromatic hydrocarbons5,000–99,9998
Selenium
Sodium
Trichloroethene/Tetrachloroethene*
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)
ItemSubstances and parametersVolume of water supplied m3/dReducedStandard
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, 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)

Check monitoring at treatment works is required only when chloramination is practised. In other circumstances, audit monitoring is required.

(iii)

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.

(iv)

To monitor for total indicative dose (for radioactivity).

1.E. coli<204
2.Coliform bacteria20–1,9991252
3.Colony counts2,000–5,99952104
4.Nitrite (ii)6,000–11,999104208
5.Residual disinfectant>12,000104365
6.Turbidity
Subject to check monitoring
7.Clostridium perfringens (i)<202
20–99924
8.Conductivity1,000–1,999612
2,000–5,9991224
6,000–9,9991836
10,000–15,9992652
16,000–32,99952104
33,000–49,99978156
50,000–67,999104208
68,000–84,999130260
85,000–101,999156312
102,000–119,999183365
120,000–241,999365730
242,000–484,9997301,460
485,000–728,9991,0952,190
Subject to audit monitoring
9.Benzene
10.Boron
11.Bromate (iii)
12.Cyanide
13.1,2 dichloroethane
14.Fluoride
15.Mercury<201
16.Nitrite (ii)20–9994
17.Pesticides and1,000–49,9998
related products50,000–89,99912
90,000–299,99924
300,000–649,99936
18.Trichloroethene/Tetrachloroethene>–650,00048
19.Tetrachloromethane
20.Chloride
21.Sulphate
22.Total organic carbon
23.Tritium
24.Gross alpha (iv)
25.Gross beta (iv)

regulation 16

SCHEDULE 4ANALYTICAL METHODOLOGY

TABLE A1

PARAMETERS FOR WHICH, SUBJECT TO REGULATION 16(7),METHODS OF ANALYSIS ARE PRESCRIBED

(1)(2)
ParameterMethod
*

The composition of m-CP agar is:

Basal medium
Tryptose30.0g
Yeast extract20.0g
Sucrose5.0g
L-cysteine hydrochloride1.0g
MgSO4.7H2O0.1g
Bromocresol purple40.0mg
Agar15.0g
Water1,000.0ml

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-cycloserine400.0mg
Polymyxine-B sulphate25.0mg
Indoxyl-β-D-glucoside60.0mg
to be dissolved in 8ml sterile water before addition
Filter-sterilised 0.5% phenolphthalein diphosphate solution20.0ml
Filter-sterilised 4.5% FeCl3.6H2O2.0ml
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 bacteriaISO 9308-1
Colony count 22°C-enumeration of culturable microorganismsPrEN ISO 6222
Colony count 37°C-enumeration of culturable microoganismsprEN ISO 6222
EnterococciISO 7899-2
Escherichia coli (E. coli)ISO 9308-1

TABLE A2

PARAMETERS IN RELATION TO WHICH METHODS OF ANALYSIS MUSTSATISFY PRESCRIBED CHARACTERISTICS

(1)(2)(3)(4)
ParametersTrueness % of prescribed concentration or value or specificationPrecision % of prescribed concentration or value or specificationLimit 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 4 NTU.

(vi)

The performance characteristics apply to the specification of 1 NTU for water leaving treatment works.

Aluminium101010
Ammonium101010
Antimony252525
Arsenic101010
Benzene252525
Benzo(a)pyrene252525
Boron101010
Bromate252525
Cadmium101010
Chloride101010
Chromium101010
Colour101010
Conductivity101010
Copper101010
Cyanide (i)101010
1,2-dichloroethane252510
Fluoride101010
Iron101010
Lead101010
Manganese101010
Mercury201020
Nickel101010
Nitrate101010
Nitrite101010
Pesticides and related products (ii)252525
Polycyclic aromatic hydrocarbons (iii)252525
Selenium101010
Sodium101010
Sulphate101010
Tetrachloroethene (iv)252510
Tetrachloromethane202020
Trichloroethene (iv)252510
Trihalomethanes:252510
Total (iii)
Turbidity (v)101010
Turbidity (vi)252525

regulation 40

SCHEDULE 5AMENDMENT 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 2001, 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 2000; or has otherwise been agreed by the Secretary of State; 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 programme 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 2001 or 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 2002 or 2003, respectively, 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 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(1)(f), after the words “Part IV of these Regulations”, the insertion of “, other than regulation 13B,”; 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 substanceConcentration or value and unit of measurementVolume of water supplied m3/dAnnual sampling frequencyEstimated population of water supply zoneAnnual sampling frequency
*

where the water originates from, or is influenced by, surface waters

Benzene1.0 μg/l
Bromate10 μgBr03/l
Clostridium perfringens* (including spores)<999S2 or R1<4,999S2 or R1
01,000 −49,999S4 or R15,000–50,000S4 or R1
Number/100ml> 50,000S8 or R2
1,2 dichloroethane3.0 μg/l
Enterococci0 Number/100ml
Nitrite0.10 mgNO2/l

TABLE 4B

PARAMETERS AND SUBSTANCES IN RELATION TO WHICH,SUBJECT TO REGULATION 21A, METHODS OF ANALYSISMUST SATISFY PRESCRIBED CHARACTERISTICS

(1)(2)(3)(4)(5)
Parameter or other substanceConcentration and unit of measurementTrueness % of concentrationPrecision % of concentrationLimit of detection % of concentration
*

Trueness, precision and limit of detection apply to the individual substances specified at 50% of the concentration in column (2)..

Antimony5.0 μgSb/l252525
Arsenic10 μgAs/l101010
Benzene1.0 μg/l252525
Boron1.0 mgB/l101010
Bromate10 μgBrO3/l252525
Copper2.0 μgCu/l101010
1,2 dichloroethane3.0 μg/l252510
Lead25 μgPb/l101010
Nickel20 μgNi/l101010
Nitrite (ex works)0.1 mgNO2/l101010
Tetrachloroethene*10 μg/l252510
Trichloroethene*10 μg/l252510

regulation 41

SCHEDULE 6PROGRAMMES 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/l 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 Secretary of State 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 } sum of concentrations

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

  • Vinyl chloride

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