# The Water Supply (Water Quality) Regulations 2018, Part 1: Group A and Group B Parameters

Extent: E+W

Table 1
Group A parameters and circumstances for monitoring
1 Sampling for this parameter in water supply zones may be substituted by sampling at supply points.
Item number (1)
Parameter (2)
Circumstances (3)
1
Aluminium
Where used as a water treatment chemical or where the water originates from, or is influenced by, surface waters
2
Ammonium
Where chloramination is practised
3
Coliform bacteria
In all circumstances
4
Colony counts 22 ° C
In all circumstances
5
Colour
In all circumstances
6
Conductivity1
In all circumstances
7
E. coli
In all circumstances
8
Hydrogen ion
In all circumstances
9
Iron
Where used as a water treatment chemical or where the water originates from, or is influenced by, surface waters
10
Manganese
Where the water originates from, or is influenced by, surface waters
11
Nitrate
Where chloramination is practised
12
Nitrite
Where chloramination is practised
13
Odour
In all circumstances
14
Residual disinfectant
In all circumstances
15
Taste
In all circumstances
16
Turbidity
In all circumstances
Note:
Table 2
Group B1 parameters and circumstances for monitoring to be used for sampling in water supply zones (or supply points)
1 Sampling for these parameters may be within water supply zones (Group B1) or at supply points (Group B2).
2 Monitoring of this parameter in water supply zones is required only where sodium hypochlorite is added after water has left the treatment works. In other circumstances, monitoring is required at supply points, see Group B2.
3 To monitor for indicative dose.
4 In the event that a single sample is taken in a year, a further sample must be taken if there is any change in relation to that supply that could affect the concentration of radionuclides in the water supply.
Item number
Parameter (2)
Circumstances
1
Aluminium
Where—
(i) not used as a water treatment chemical; or
(ii) the water neither originates from, nor is influenced by, surface waters.
2
Ammonium
Where chloramination is not practised
3
Antimony
In all circumstances
4
Arsenic
In all circumstances
5
Benzene 1
In all circumstances
6
Benzo(a)pyrene
In all circumstances
7
Boron 1
In all circumstances
8
Bromate 2
In all circumstances
9
Cadmium
In all circumstances
10
Chloride 1
In all circumstances
11
Chromium
In all circumstances
12
Clostridium perfringens (including spores)
In all circumstances
13
Copper
In all circumstances
14
Cyanide 1
In all circumstances
15
1, 2 dichloroethane 1
In all circumstances
16
Enterococci
In all circumstances
17
Fluoride 1
In all circumstances
18
Gross alpha 134
In all circumstances
19
Gross beta 134
In all circumstances
20
Iron
Where—
(i) not used as a flocculant; or
(ii) the water neither originates from, nor is influenced by, surface waters.
21
Lead
In all circumstances
22
Manganese
Where the water neither originates from, nor is influenced by, surface waters.
23
Mercury 1
In all circumstances
24
Nickel
In all circumstances
25
Nitrate
Where chloramination is not practised.
26
Nitrite
Where chloramination is not practised.
27
Pesticides and related products 1
In all circumstances
28
Polycyclic aromatic hydrocarbon
In all circumstances
29
Radon 14
In all circumstances
30
Selenium
In all circumstances
31
Sodium
In all circumstances
32
Sulphate 1
In all circumstances
33
Tetrachloroethene 1
In all circumstances
34
Tetrachloromethane 1
In all circumstances
Total organic carbon 1
35
Trichloroethene
In all circumstances
Trihalomethanes: Total
36
Tritium 14
In all circumstances
Notes:
Table 3
Group B2 parameters and circumstances for monitoring to be used for sampling at works or in water supply zones (or supply points)
1 Sampling for these parameters may be within water supply zones (Group B1) or at supply points (Group B2).
2 Monitoring is required at supply points where sodium hypochlorite is not added after water has left the treatment works. In other circumstances, see Group B1.
3 To monitor for indicative dose.
4 In the event that a single sample is taken in a year, a further sample must be taken if there is any change in relation to that supply that could affect the concentration of radionuclides in the water supply.
Item number
Parameter 2
Circumstances
1
Benzene 1
In all circumstances
2
Boron 1
In all circumstances
3
Bromate 2
In all circumstances
4
Chloride 1
In all circumstances
5
Colstridium perfringens (including spores)(1)
In all circumstances
6
Cyanide 1
In all circumstances
7
1, 2 dichloroethane 1
In all circumstances
8
Fluoride 1
In all circumstances
9
Gross alpha 134
In all circumstances
10
Gross beta 134
In all circumstances
11
Indicative dose (1)
In all circumstances
12
Mercury 1
In all circumstances
13
Nitrite
When chloramination is not practised.
14
Pesticides and related products 1
In all circumstances
15
Radon 14
In all circumstances
16
Sulphate 1
In all circumstances
17
Tetrachloroethene/Trichloroethene(1)
In all circumstances
18
Tetrachloromethane 1
In all circumstances
19
Total organic carbon 1
20
. . .
. . .
21
Tritium 14
In all circumstances
Notes:
Table 4
Group A1 parameters
Item number
Parameter
1
Coliform bacteria
2
E. coli
3
Residual disinfectant
Table 5
Group A2 parameters
Item number
Parameter
1
Coliform bacteria
2
Colony counts 22° C
3
E.coli
4
Nitrite
5
Residual disinfectant
6
Turbidity
Table 6
Group A3 parameters
Item number
Parameter
1
Conductivity
Table 7
Group A4 parameters
Item number
Parameter
1
Aluminium
2
Ammonium
3
Colony counts 22° C
4
Colour
5
Conductivity
6
Hydrogen ion
7
Iron
8
Manganese
9
Nitrate
10
Nitrite
11
Odour
12
Taste
13
Turbidity

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Source: https://www.legislation.gov.uk/wsi/2018/647/schedule/3/part/1 (the official version)
Page: https://openlegislation.uk/water-supply-water-quality-regulations-2018/schedule-3/part-1
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.