# The Water Supply (Water Quality) Regulations (Northern Ireland) 2002, Part IV: MONITORING

Extent: N.I.

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
Colony Counts
6.
Colour
7.
Conductivity
8.
Escherichia coli (E. coli)
9.
Hydrogen ion
10.
Iron
When used as flocculant or where the water originates from, or is influenced by, surface waters
11.
Manganese
Where the water originates from, or is influenced by, surface waters
12.
Nitrate
When chloramination is practised
13.
Nitrite
When chloramination is practised
14.
Odour
15.
Taste
16.
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 }
(including spores) }
Colony counts }
Colour }
<100
1
2
Conductivity }
100–4,999
2
4
Hydrogen ion }
5,000–9,999
6
12
Iron }
10,000–29,999
12
24
Manganese }
30,000–49,999
18
36
Nitrate }
50,000–79,999
26
52
Nitrite }
80,000–100,000
38
76
Odour }
Taste }
Turbidity }
Parameters subject to audit monitoring
Aluminium }
Antimony }
Arsenic }
Benzene }
Benzo(a)pyrene }
Boron }
Bromate }
Cadmium }
Chromium }
Copper }
Cyanide }
1,2 dichloroethane }
<100
1
Enterococci }
100–4,999
4
Fluoride }
5,000–100,000
8
Iron }
Lead }
Manganese }
Mercury }
Nickel }
Nitrate }
Nitrite }
Pesticides and related products }
Polycyclic aromatic hydrocarbons }
Selenium }
Sodium }
Trichloroethene/Tetrachloroethene }
Tetrachloromethane }
Trihalomethanes }
<100
1
Chloride }
100–4,999
4
Sulphate }
5,000–100,000
8
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, except nitrite, subject to notes (ii) and (iii);
(i)Check monitoring is required only in respect of surface waters (see regulation 6(2) and Table 1 in Schedule 3).
(ii)Sampling at treatment works when chloramination is practised.
(iii)Sampling at treatment works when chloromination is not practised.
(iv)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.
(v)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 }
<20
1
14.
Fluoride }
20–999
4
15.
Mercury }
1,000–49,999
8
16.
Nitrite }
50,000–89,999
12
17.
Pesticides and }
90,000–299,999
24
related products }
300,000–649,999
36
18.
Trichloroethene }
≥650,000
48
Tetrachloroethene }
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/nisr/2002/331/schedule/3/part/IV (the official version)
Page: https://openlegislation.uk/water-supply-water-quality-regulations-northern-ireland-2002/schedule-3/part-IV
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.