The Private Water Supplies (Wales) Regulations 2010

PART 2Analytical methods

Table 1

Prescribed methods of analysis

ParameterMethod
*

Use the following method to make m-CP agar :

Make a basal medium consisting of—

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.

Dissolve—

D-cycloserine400.0mg
Polymyxine-B sulphate25.0mg
Indoxyl-β-D-glucoside60.0mg

into 8ml sterile water and add it to the medium.

Add to the medium—

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 bacteriaBS-EN ISO 9308-1
Colony count 22°C — enumeration of culturable microorganismsBS-EN ISO 6222
Colony count 37°C — enumeration of culturable microorganismsBS-EN ISO 6222
Enterococci BS-EN ISO 7899-2
Escherichia coli (E. coli)BS-EN ISO 9308-1
Pseudomonas aeruginosaBS-EN-ISO 12780

Table 2

Prescribed performance characteristics for methods of analysis

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 surface waters or ground waters influenced by surface water.

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:
Total (iii)252510
Turbidity (v)101010
Turbidity (vi)252525