# The Water Supply (Water Quality) Regulations 2000, Schedule 3: MONITORING


TABLE 1
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.
Colour
6.
Conductivity
7.
Escherichia coli (E. coli)
8.
Hydrogen ion concentration
9.
Iron
When used as flocculant 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
When chloramination is practised
12.
Nitrite
When chloramination is practised
13.
Odour
14.
Taste
15.
Turbidity
TABLE 2
ANNUAL SAMPLING FREQUENCIES: WATER SUPPLY ZONES
(1)
(2)
(3)
(4)
Substances and parameters subject to check monitoring
Estimated population of water supply zone
Reduced
Standard
Notes: *Sampling for these parameters may be within water supply zones or at supply points as specified in Table 3, subject to notes (ii) and (iii) below.
(i)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.
(ii)Check monitoring in water supply zones is required only where chloramination is practised. In other circumstances audit monitoring is required.
(iii)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.
(iv)To monitor for total indicative dose (for radioactivity).
E. coli
<100
4
Coliform bacteria Residual disinfectant
>–100
12 per 5,000 population
Aluminium
Ammonium
Clostridium perfringens
Colony counts
<100
1
2
Colour
100–4,999
2
4
Conductivity
5,000–9,999
6
12
Hydrogen ion
10,000–29,999
12
24
Iron
30,000–49,999
18
36
Manganese
50,000–79,999
26
52
Nitrate
80,000–99,999
38
76
Nitrite
Odour
Taste
Turbidity
Parameters subject to audit monitoring
Aluminium
Antimony
Arsenic
Benzene
<100
1
Benzo(a)pyrene
100–4,999
4
Boron
5,000–99,999
8
Bromate
Cadmium
Chromium
Copper
Cyanide
1,2 dichloroethane
Enterococci
Fluoride
Iron
Lead
Manganese
Mercury
Nickel
Nitrate
Nitrite
Pesticides and related products
<100
1
100–4,999
4
Polycyclic aromatic hydrocarbons
5,000–99,999
8
Selenium
Sodium
Trichloroethene/Tetrachloroethene
Trihalomethanes
Chloride
Sulphate
Total organic carbon
Tritium
Gross alpha
Gross beta
TABLE 3
ANNUAL SAMPLING FREQUENCIES: TREATMENT WORKS OR SUPPLY POINTS
(1)
(2)
(3)
(4)
(5)
Item
Substances and parameters
Volume of water supplied m3/d
Reduced
Standard
Notes: *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, subject to notes (ii) and (iii) below.
(i)Check monitoring is required only in respect of surface waters (see regulation 6(2) and Table 1 in Schedule 3).
(ii)Check monitoring at treatment works is required only when chloramination is practised. In other circumstances, audit monitoring is required.
(iii)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.
(iv)To monitor for total indicative dose (for radioactivity).
1.
E. coli
<20
4
2.
Coliform bacteria
20–1,999
12
52
3.
Colony counts
2,000–5,999
52
104
4.
Nitrite
6,000–11,999
104
208
5.
Residual disinfectant
>12,000
104
365
6.
Turbidity
Subject to check monitoring
7.
Clostridium perfringens
<20
2
20–999
2
4
8.
Conductivity
1,000–1,999
6
12
2,000–5,999
12
24
6,000–9,999
18
36
10,000–15,999
26
52
16,000–32,999
52
104
33,000–49,999
78
156
50,000–67,999
104
208
68,000–84,999
130
260
85,000–101,999
156
312
102,000–119,999
183
365
120,000–241,999
365
730
242,000–484,999
730
1,460
485,000–728,999
1,095
2,190
Subject to audit monitoring
9.
Benzene
10.
Boron
11.
Bromate
12.
Cyanide
13.
1,2 dichloroethane
14.
Fluoride
15.
Mercury
<20
1
16.
Nitrite
20–999
4
17.
Pesticides and
1,000–49,999
8
related products
50,000–89,999
12
90,000–299,999
24
300,000–649,999
36
18.
Trichloroethene/Tetrachloroethene
>–650,000
48
19.
Tetrachloromethane
20.
Chloride
21.
Sulphate
22.
Total organic carbon
23.
Tritium
24.
Gross alpha
25.
Gross beta

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Source: https://www.legislation.gov.uk/uksi/2000/3184/schedule/3 (the official version)
Page: https://openlegislation.uk/water-supply-water-quality-regulations-2000/schedule-3
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.