# The Water Supply (Water Quality) Regulations 2018, Schedule 5: ANALYTICAL METHODOLOGY

Extent: E+W

Table A1
Parameters for which, subject to Regulation 15(7), methods of analysis are specified
(1) Parameter
(2)Method of analysis
E. coli and coliform bacteria
EN ISO 9308-1 or EN ISO 9308-2
Enterococci
EN ISO 7899-2
Pseudomonas aeruginosa
EN ISO 16266
Enumeration of culturable microorganisms
– colony count 22°c
EN ISO 6222
Enumeration of culturable microorganisms
– colony count 36°c
EN ISO 6222
Clostridium perfringens including spores
EN ISO 14189
Table A2
Parameters in relation to which methods of analysis must satisfy prescribed characteristics
...
Table A3
Minimum performance characteristic “uncertainty of measurement”
The uncertainty of measurement laid down in this table must not be used as an additional tolerance to the parametric values set out in Schedules 1 and 2.
1 “Uncertainty of measurement” is a non-negative parameter characterising the dispersion of the quantity values being attributed to a measurement, based on the information used. The performance criterion for measurement uncertainty (k = 2) is at least the percentage of the parametric value stated in the table. If the value of uncertainty of measurement cannot be met, the best available technique must be selected (up to 60 % of the parametric value).
2 The method determines total cyanide in all forms.
3 Reference method: European standard EN ISO 8467 entitled “Water quality - Determination of permanganate index (ISO 8467)”.
4 The performance characteristics for individual pesticides are given as an indication. 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.
5 The performance characteristics apply to individual substances, specified at 25% of the parametric value in Part 1 of Table B in Schedule 1.
6 The performance characteristics apply to individual substances, specified at 50 % of the parametric value in Part 1 of Table B in Schedule 1.
7 The uncertainty of measurement must be estimated at the level of 3 mg/l of the total organic carbon (TOC) in accordance with European standard EN 1484 entitled “Water analysis - Guidelines for the determination of total organic carbon and dissolved organic carbon” and dissolved organic carbon (DOC) shall be used.
8 The uncertainty of measurement must be estimated at the level of 1,0 NTU in accordance with European standard EN ISO 7027-1 entitled “Water quality - Determination of turbidity - Part 1: Quantitative methods (ISO 7027-1”.
(1)Parameter
(2)Uncertainty of measurement % of the parametric value (except for pH) 1
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
Colour
20
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
Oxidisability 4
50
Pesticides 5
30
Polycyclic aromatic hydrocarbons 6
50
Selenium
40
Sodium
15
Sulphate
15
Tetrachloroethene 6
30
Tetrachloromethane
30
Trichloroethene 7
40
Trihalomethanes: total 6
40
Total organic carbon 8
30
Turbidity 9
30
Notes:

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Source: https://www.legislation.gov.uk/wsi/2018/647/schedule/5 (the official version)
Page: https://openlegislation.uk/water-supply-water-quality-regulations-2018/schedule-5
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.