The Water Supply (Water Quality) Regulations 2010 (revoked)

Regulations 2 and 4

SCHEDULE 1 E+W PRESCRIBED CONCENTRATIONS AND VALUES

Table A

Microbiological Parameters

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

Table B

Chemical Parameters

Notes:
1 The parametric value refers to the residual monomer concentration in the water as calculated according to specifications of the maximum release from the corresponding polymer in contact with the water. This is controlled by product specification.
2 See also regulation 6(6).
3 See also regulation 4(2)(d).
4 See the definition of “pesticides and related products” in regulation 2.
5 The parametric value applies to each individual pesticide.
6 “Pesticides: Total” means the sum of the concentrations of the individual pesticides detected and quantified in the monitoring procedure.
7 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.
8 The parametric value applies to the sum of the concentrations of the individual compounds detected and quantified in the monitoring process.
9 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.
Part I: National requirements
Item	Parameters	Concentration or Value (maximum)	Units of Measurement	Point of compliance
1	Acrylamide	0.10	μg/l	1
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 2	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	1
14	Fluoride	1.5	mgF/l	Consumers' taps
15	Lead 2	(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 2	20	μgNi/l	Consumers' taps
18	Nitrate 3	50	mgNO3/l	Consumers' taps
19	Nitrite 3	0.50	mgNO2/l	Consumers' taps
		0.10		Treatment Works
20	Pesticides 45
	Aldrin)	0.030	μg/l	Consumer's taps
	Dieldrin)
	Heptachlor)
	Heptachlor
	epoxide)
	other pesticides	0.10	μg/l	Consumers' taps
21	Pesticides: Total 6	0.50	μg/l	Consumers' taps
22	Polycyclic aromatic hydrocarbons 7	0.10	μg/l	Consumers' taps
23	Selenium	10	μgSe/l	Consumers' taps
24	Tetrachloroethene and Trichloroethene 8	10	μg/l	Consumers' taps
25	Trihalomethanes: Total 9	100	μg/l	Consumers' taps
26	Vinyl chloride	0.50	μg/l	1

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 E+W INDICATOR PARAMETERS

Notes:
1 The water should not be aggressive.
2 F1 . . .
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
			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
		6.5 (minimum)	pH value
8	Sulphate 1	250	mgSO4/l	Supply point3
9	F2 . . .	F2 . . .	F2 . . .	F2 . . .
10	Total organic carbon (TOC)	No abnormal change	mgC/l	Supply point3
11	F3 . . .	F3 . . .	F3 . . .	F3 . . .
12	Turbidity	1	NTU	Treatment works

Textual Amendments

F1 Words in Sch. 2 omitted (14.4.2016) by virtue of The Water Supply (Water Quality) (Amendment) Regulations 2016 (S.I. 2016/410), regs. 1(1), 4(c)

F2 Words in Sch. 2 table omitted (14.4.2016) by virtue of The Water Supply (Water Quality) (Amendment) Regulations 2016 (S.I. 2016/410), regs. 1(1), 4(a)

F3 Words in Sch. 2 table omitted (14.4.2016) by virtue of The Water Supply (Water Quality) (Amendment) Regulations 2016 (S.I. 2016/410), regs. 1(1), 4(b)

Regulation 6A

[F4 SCHEDULE 2A E+W Radioactive substances parameters

Textual Amendments

F4 Sch. 2A inserted (14.4.2016) by The Water Supply (Water Quality) (Amendment) Regulations 2016 (S.I. 2016/410), reg. 1(1), 5, Sch. 1

Parametric values for radon, tritium and ID of water intended for human consumption

Parameters	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.
(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		mSv
Radon	100		Bq/1
Tritium (for radioactivity)		100	Bq/l

SCHEDULE 3 E+W MONITORING

PART IV

Table 1 E+W 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 E+W Annual Sampling Frequencies: Water Supply Zones

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

1 Where the population is not an exact multiple of 5,000, the population figure should be rounded up to the nearest multiple of 5,000.
2 Sampling for these parameters may be within water supply zones or at supply points as specified in Table 3, subject to notes (iii) and (iv) below.
3 Check monitoring in water supply zones is required only where chloramination is practised. In other circumstances audit monitoring is required.
4 Audit monitoring in water supply zones is required only where sodium hypochlorite is added after water has left the treatment works. In other circumstances, audit monitoring is required at supply points.
5 F5 ...
(1)	(2)	(3)	(4)
Substances and parameters subject to check monitoring	Estimated population of water supply zone	Reduced	Standard
Subject to check monitoring
E coli	<100		4
Coliform bacteria	≥100		12 per 5,000 population1
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)2
Colony counts
Colour
Conductivity2
Hydrogen ion
Iron
Manganese
Nitrate 3
Nitrite 3
Odour
Taste
Turbidity
Subject to audit monitoring
Aluminium	<100 100—4,999 5,000—100,000		1 4 8
Antimony
Arsenic
Benzene2
Benzo(a)pyrene
Boron2
Bromate 4
Cadmium
Chromium
Clostridium perfringens (including spores)
Copper
Cyanide2
1,2 dichloroethane2
Enterococci
Fluoride2
Iron
Lead
Manganese
Mercury2
Nickel
Nitrate 3
Nitrite 3
Pesticides and related products 2
Polycyclic aromatic hydrocarbons
[F6 Radon(b)]
Selenium
Sodium
Trichloroethene /Tetrachloroethene2
Tetrachloromethane2
Trihalomethanes
Chloride2
Sulphate2
Total organic carbon2
Tritium2
[F7 Indicative dose (for radioactivity)(b)]

Textual Amendments

F5 Words in Sch. 3 omitted (14.4.2016) by virtue of The Water Supply (Water Quality) (Amendment) Regulations 2016 (S.I. 2016/410), regs. 1(1), 6(a)(iii)

F6 Words in Sch. 3 table inserted (14.4.2016) by The Water Supply (Water Quality) (Amendment) Regulations 2016 (S.I. 2016/410), regs. 1(1), 6(a)(i)

F7 Words in Sch. 3 table substituted (14.4.2016) by The Water Supply (Water Quality) (Amendment) Regulations 2016 (S.I. 2016/410), regs. 1(1), 6(a)(ii)

Regulation 9

Table 3 E+W 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 Sampling at treatment works when chloramination is practised.
2 Check monitoring is required only in respect of surface waters (see regulation 6(2) and Table 1 in Schedule 3).
3 Audit monitoring at supply points is required only where sodium hypochlorite is not added after water has left the treatment works. In other circumstances, audit monitoring is required in water supply zones.
4 Sampling at treatment works when chloramination is not practised.
5F8 ...
(1)	(2)	(3)	(4)	(5)
Item	Substances and parameters	Volume of water supplied m3/d	Reduced	Standard
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 1
5.	Residual disinfectant
6.	Turbidity
Subject to check monitoring
7.	Clostridium perfringens2	<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 3
11A.	Clostridium perfringens (including spores)
12.	Cyanide
13.	1,2 dichloroethane
14.	Fluoride
15.	Mercury
16.	Nitrite 4
17.	Pesticides and Related products
[F9 17A	Radon]
18.	Trichloroethene
	Tetrachloroethene
19.	Tetrachloromethane
20.	Chloride
21.	Sulphate
22.	Total organic carbon
23.	Tritium
24.	[F10 Indicative dose (for radioactivity)(b)
25.]

Textual Amendments

F8 Words in Sch. 3 omitted (14.4.2016) by virtue of The Water Supply (Water Quality) (Amendment) Regulations 2016 (S.I. 2016/410), regs. 1(1), 6(b)(iii)

F9 Words in Sch. 3 table inserted (14.4.2016) by The Water Supply (Water Quality) (Amendment) Regulations 2016 (S.I. 2016/410), regs. 1(1), 6(b)(i)

F10 Words in Sch. 3 table substituted (14.4.2016) by The Water Supply (Water Quality) (Amendment) Regulations 2016 (S.I. 2016/410), regs. 1(1), 6(b)(ii)

Regulation 6A

[F11 SCHEDULE 3A E+W Monitoring of radioactive substances

Textual Amendments

F11 Sch. 3A inserted (14.4.2016) by The Water Supply (Water Quality) (Amendment) Regulations 2016 (S.I. 2016/410), reg. 1(1), 7, Sch. 2

Radon E+W

1.— (1) In relation to the radon parameter in the radioactive substances parameters table, a water undertaker—

(a) must ensure that a representative survey is carried out in accordance with sub-paragraph (2) to determine the likelihood of a supply failing to comply with the relevant parametric concentration or value specified in the radioactive substances parameters table; and

(b) must carry out monitoring where there is reason to believe, on the basis of the results of the representative surveys or other reliable information, including any risk assessment carried out in accordance with regulation 28, that the parametric value for the radon parameter laid down in the radioactive substances parameters table might be exceeded.

(2) A representative survey must be designed in such a way—

(a) as to be capable of determining the scale and nature of likely exposure to radon in water intended for human consumption originating from different types of groundwater sources and wells in different geological areas; and

(b) that underlying parameters, especially the geology and hydrology of the area, radioactivity of rock or soil, and well type, can be identified and used to direct further action to areas of likely high exposure.

Tritium E+W

2.— (1) In relation to the tritium parameter in the radioactive substances parameters table, a water undertaker—

(a) must carry out monitoring where an anthropogenic source of tritium or other artificial radionuclides is present within a water supply zone and it cannot be shown on the basis of other surveillance programmes or investigations, including any risk assessment carried out in accordance with regulation 28, that the level of tritium is below the parametric value listed in the radioactive substances parameters table; and

(b) must carry out an investigation of the presence of other artificial radionuclides if the concentration of tritium exceeds the parametric value listed in the radioactive substances parameters table.

(2) Where monitoring is required by sub-paragraph (1) samples must be taken in accordance with regulation 9(1) and (3).

Indicative Dose E+W

3.— (1) In relation to the indicative dose (“ID”) parameter in the radioactive substances parameters table, a water undertaker must carry out monitoring where a source of artificial radioactivity or elevated natural radioactivity is present in a water supply zone and it cannot be shown on the basis of other surveillance programmes or investigations, including any risk assessment carried out in accordance with regulation 28, that the level of ID is below the parametric value listed the radioactive substances parameters table.

(2) Where monitoring is required by sub-paragraph (1) in relation to artificial radionuclides samples must be taken in accordance with regulation 9(1) and (3).

(3) Where monitoring is required by sub-paragraph (1) in relation to a source of elevated natural radioactivity—

(a) the Welsh Ministers must specify, by notice in writing to the water undertaker, the frequency of the monitoring required of—

(i) gross alpha activity;

(ii) gross beta activity; or

(iii) individual natural radionuclides,

depending on the screening strategy adopted by the water undertaker pursuant to Schedule 5; and

(b) the frequency of monitoring required under sub-paragraph (a) may vary from a single check measurement to the frequencies required for sampling in accordance with regulation 9(1).

(4) Where a single check for natural radioactivity is specified under paragraph (3)(a), the water undertaker must carry out a further check if any change occurs in relation to the supply which is likely to influence the concentrations of radionuclides in the supply.

Water treatment E+W

4.   Where treatment to reduce the level of radionuclides in a water supply zone has been undertaken, to verify the continued efficacy of that treatment, the water undertaker must—

(a) monitor the supply for total indicative dose, radon and tritium in accordance the provisions of this Schedule; and

(b) take samples in accordance with regulation 9(1) and (3).

Averaging E+W

5.   Where a parametric value in the radioactive substances parameters table is exceeded in relation to a particular sample taken by a water undertaker, the Welsh Ministers must specify, by notice in writing to the water undertaker, the extent of resampling necessary to ensure that the measured values are representative of an average activity concentration for a full year.]

Regulation 16

SCHEDULE 4 E+W ANALYTICAL METHODOLOGY

Regulation 16

Table A1 E+W 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 E+W Parameters for which, Subject to Regulation 16(7), Methods of Analysis are Prescribed

Notes:
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.
3 The performance characteristics apply to the individual substances specified at 25% of the parametric value in Part I of Table B in Schedule 1.
4 The performance characteristics apply to the individual substances specified at 50% of the parametric value in Part I of Table B in Schedule 1.
5 The performance characteristics apply to the prescribed value of 4NTU.
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

Regulation 6A

[F12 SCHEDULE 5 E+W Monitoring for indicative dose and analytical performance characteristics

Textual Amendments

F12 Sch. 5 inserted (14.4.2016) by The Water Supply (Water Quality) (Amendment) Regulations 2016 (S.I. 2016/410), reg. 1(1), 8, Sch. 3

Monitoring for compliance with the indicative dose E+W

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

2.   The strategies referred to in paragraph 1 may include screening for–

(a) certain radionuclides or individual radionuclide; or

(b) gross alpha activity or gross beta activity (where appropriate gross beta activity may be replaced by residual beta activity after subtraction of the K-40 activity concentration).

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

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

4.   A water undertaker must, in deciding which radionuclides require to be measured for each supply, take into account all relevant information about likely sources of radioactivity.

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

5.   Subject to paragraph 6 the recommended screening values are–

(a) 0,1Bq/l for gross alpha activity; and

(b) 1,0Bq/l for gross beta activity.

6.   If the gross alpha activity exceeds 0,1Bq/l or the gross beta activity exceeds 1,0Bq/l, analysis for specific radionuclides is required.

7.   The Welsh Ministers may set alternative screening levels for gross alpha activity and gross beta activity where it can be demonstrated by the water undertaker that the alternative levels are in compliance with an indicative dose of 0,1 mSv.

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

Calculation of the indicative dose E+W

9.   The indicative dose must be calculated from–

(a) the measured radionuclide concentrations and the dose coefficients laid down in Annex III, Table A of Directive 96/29/Euratom; or

(b) more recent information recognised by the Welsh Ministers, on the basis of the annual intake of water (730 1 for adults).

10.   Where the following formula is satisfied, it can be assumed that the indicative dose is less than the parametric value of 0,1 mSv and no further investigation is required–

where:

• C_i(obs) = observed concentration of radionuclide i

• C_i(der) = derived concentration of radionuclide i

• n = number of radionuclides detected.

Derived concentrations for radioactivity in water intended for human consumption

Origin	Nuclide	Derived concentration
(1) This table includes values for the most common natural and artificial radionuclides; these are precise values, calculated for a dose of 0,1 mSV, an annual intake of 730 litre and using the dose coefficients laid down in Annex III, Table A of Directive 96/29/ Euratom; derived concentrations for other radionuclides can be calculated on the same basis, and values can be updated on the basis of more recent information recognised by the Welsh Ministers.
(2) This table allows only for the radiological properties of uranium, not for its chemical toxicity.
Natural	U-238	3,0 Bq/1
	U-234	2,8 Bq/1
	Ra-226	0,5 Bq/1
	Ra-228	0,2 Bq/1
	Pb-210	0,2 Bq/1
	Po-210	0,1 Bq/1
Artificial	C-14	240 Bq/1
	Sr-90	4,9 Bq/1
	Pu-239/Pu-240	0,6 Bq/1
	Am-241	0,7 Bq/1
	Co-60	40 Bq/1
	Cs-134	7,2 Bq/1
	Cs-137	11 Bq/1
	1-131	6,2 Bq/1

Performance characteristics and methods of analysis E+W

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

Parameters and radionuclides	Limit of detection (Notes 1,2)	Notes
Tritium	10 Bq/1	Note 3
Radon	10 Bq/1	Note 3
gross alpha	0,04 Bq/1	Note 4
gross beta	0,4 Bq/1	Note 4
U-238	0,02 Bq/1
U-234	0,02 Bq/1
Ra-226	0,04 Bq/1
Ra-228	0,02 Bq/1	Note 5
Pb-210	0,02 Bq/1
Po-210	0,01 Bq/1
C-14	20 Bq/1
Sr-90	0,4 Bq/1
Pu-239/Pu-240	0,04 Bq/1
Am-241	0,06 Bq/1
Co-60	0,5 Bq/1
Cs-134	0,5 Bq/1
Cs-137	0,5 Bq/1
I-131	0,5 Bq/1

Note 1: The limit of detection must be calculated according to the ISO standard 11929: Determination of the characteristic limits (decision threshold, detection limit, and limits of confidence interval) for measurements of ionising radiation – Fundamentals and application, with probabilities of errors of 1st and 2nd kind of 0,05 each.

Note 2: Measurement uncertainties must be calculated and reported as complete standard uncertainties, or as expanded uncertainties with an expansion factor of 1,96 according the ISO Guide for the Expression of Uncertainty in Measurement.

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

Note 4: The limit of detection for gross alpha activity and gross beta activities are 40% of the screening values of 0,1 and 1,0 Bq/1 respectively.

Note 5: This limit of detection applies only to initial screening for indicative dose for a new water source; if initial checking indicates that it is not plausible that Ra-228 exceeds 20% of the derived concentration, the limit of detection may be increased to 0,08 Bq/1 for routine Ra-228 nuclide specific measurements, until a subsequent re-check is required.]