The Private Water Supplies (Wales) Regulations 2017

PART 2 Analytical methods

Table 1

Prescribed methods of analysis for microbiological parameters

Parameter	Method
Escherichia coli (E. coli)	EN ISO 9308-1 or EN ISO 9308-2
Enterococci	EN ISO 7899-2
Pseudomonas aeruginosa	EN-ISO 16266
Colony count 22°C — enumeration of culturable microorganisms	EN ISO 6222
Colony count 36°C — enumeration of culturable microorganisms	EN ISO 6222
Clostridium perfringens (including spores)	EN ISO 14189

Table 2

Prescribed performance characteristics for methods of analysis for chemical and indicator parameters: trueness, precision and limit of detection (on or before 31 December 2019)

Parameter	Trueness % of prescribed concentration or value or specification (except for pH)	Precision % of prescribed concentration or value or specification (except for pH)	Limit of detection % of prescribed concentration or value or specification (except for pH)
(1) The method of analysis should determine total cyanide in all forms.
(2) EN ISO 8476.
(3) The performance characteristics apply to each individual pesticide and will depend on the pesticide concerned. Values for the uncertainty of measurement as low as 30% can be achieved for several pesticides, higher values up to 80% may be allowed for a number of pesticides.
(4) The performance characteristics apply to the individual substances specified at 25% of the parametric value in Table B of Part 1 of Schedule 1.
(5) The performance characteristics apply to the individual substances specified at 50% of the parametric value in Table B of Part 1of Schedule 1.
(6) The performance characteristics apply to the prescribed value of 4 NTU.
(7) The performance characteristics apply to the specification of 1 NTU for surface waters or ground waters influenced by surface water.
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
Hydrogen ion concentration pH (expressed in pH units)	0.2	0.2
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
Oxidisability(2)
Pesticides and related products(3)	25	25	25
Polycyclic aromatic hydrocarbons(4)	25	25	25
Selenium	10	10	10
Sodium	10	10	10
Sulphate	10	10	10
Tetrachloroethene(5)	25	25	10
Tetrachloromethane	20	20	20
Trichloroethene(5)	25	25	10
Trihalomethanes: Total(4)
	25	25	10
Turbidity(6)	10	10	10
Turbidity(7)	25	25	25

Table 3

Method of analysis for chemical and indicator parameters: uncertainty of measurement⁽¹⁾

Parameter	Uncertainty of measurement % of parametric value (except for pH)
(1) The uncertainty of measurement must not be used as an additional tolerance to the parametric values set out in Schedule 1.
(2) If the value of uncertainty of measurement cannot be met, the best available technique should be selected (up to 60%).
(3) The method of analysis should determine total cyanide in all forms.
(4) EN ISO 8476.
(5) The performance characteristics apply to each individual pesticide and will depend on the pesticide concerned. Values for the uncertainty of measurement as low as 30% can be achieved for several pesticides, higher values up to 80% may be allowed for a number of pesticides.
(6) The performance characteristics apply to the individual substances specified at 25% of the parametric value in Table B of Part 1 of Schedule 1.
(7) The performance characteristics apply to the individual substances specified at 50% of the parametric value in Table B of Part 1 of Schedule 1.
(8) The uncertainty of measurement must be estimated at the level of 3mg/l of TOC. CEN 1484 Guidelines for the determination of TOC and dissolved organic carbon must be used.
(9) The uncertainty of measurement must be estimated at the level of 1,0 NTU in accordance with EN ISO 7027.
Aluminium	25
Ammonium	40
Antimony	40
Arsenic	30
Benzene	40
Benzo(a)pyrene(2)	50
Boron	25
Bromate	40
Cadmium	25
Chloride	15
Chromium	30
Conductivity	20
Copper	25
Cyanide(3)	30
1,2-dichloroethane	40
Fluoride	20
Hydrogen ion concentration pH (expressed in pH units)	0.2
Iron	30
Lead	25
Manganese	30
Mercury	30
Nickel	25
Nitrate	15
Nitrite	20
Oxiedisability(4)	50
Pesticides(5)	30
Polycyclic aromatic hydrocarbons(6)	50
Selenium	40
Sodium	15
Sulphate	15
Tetrachloroethene(7)	30
Trichloroethene(7)	40
Trihalomethanes: total(6)	40
Total organic carbon (TOC)(8)	30
Turbidity(9)	30