# The Water Supply (Water Quality) Regulations (Northern Ireland) 2017, Paragraph 1


(1) A monitoring programme established under Part 4 of these Regulations must—
(a) verify that—
(i) the measures in place to control risks to human health throughout the water supply chain (from the catchment area through abstraction, treatment and storage to distribution) are working effectively; and
(ii) water at the point of compliance is wholesome;
(b) provide information on the quality of water supplied to—
(i) demonstrate whether or not the water complies with prescribed concentrations and values for parameters in Schedule 1;
(ii) determine the organoleptic and microbiological quality of the water; and
(iii) establish the effectiveness of the treatment of the water, particularly of disinfection where it is used.
(c) identify the most appropriate means of mitigating any risk to human health; and
(d) have regard to Part 5.
(2) A monitoring programme must consist of either—
(a) the collection and analysis of discrete water samples; or
(b) measurement recorded by a continuous monitoring process; or
(c) a combination of both of the methods described in sub-paragraphs (a) and (b).
(3) In addition, monitoring programmes may consist of—
(a) inspections of records of the functionality and maintenance status of equipment; and/or
(b) inspections of the catchment area, water abstraction, treatment, storage and distribution infrastructure.
(4) The monitoring programme may be based on a risk assessment as set out in regulation 30.
(5) When choosing appropriate parameters and other micro-organisms, parasites or substances for monitoring programmes, local conditions for each water supply system must be taken into consideration.
TABLE 1
PARAMETERS AND CIRCUMSTANCES FOR GROUP A MONITORING
1 A supply which consists of both groundwater and surface water is deemed to be a supply which consists only of surface water.
(1) Item
(2) Parameter
(3) Circumstances
1
Aluminium
If used as water treatment chemicals or where the water originates from, or is influenced by, surface waters
2
Ammonium
Where chloramination is practised
3
Coliform bacteria
In all supplies
4
Colony Counts
In all supplies
5
Colour
In all supplies
6
Conductivity
In all supplies
7
Disinfectant residual
When disinfection treatment is practised
8
Escherichia coli (E. coli)
In all supplies
9
Indicative Dose
Where there is treatment in place to reduce the level of radionuclides in water intended for human consumption.
10
Iron1
If used as water treatment chemicals or where the water originates from, or is influenced by, surface waters
11
Manganese1
Where the water originates from, or is influenced by, surface waters
12
Nitrate
Where chloramination is practised
13
Nitrite
Where chloramination is practised
14
Odour
In all supplies
15
pH (Hydrogen ion)
In all supplies
16
Radon
Where there is treatment in place to reduce the level of radionuclides in water intended for human consumption.
17
Taste
In all supplies
18
Tritium
Where there is treatment in place to reduce the level of radionuclides in water intended for human consumption.
19
Turbidity
In all supplies
TABLE 2
Annual Sampling Frequencies: Water Supply Zones
This table sets out the annual sampling frequencies for all the substances and parameters in column 1. These are determined for each water supply zone according to its estimated population (column 2).
1 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.
2 Sampling for these parameters may be within water supply zones or at supply points as specified in Table 3, subject to notes (5) and (6) below.
3 Group A monitoring in water supply zones is required only where chloramination is practised. In other circumstances Group B monitoring is required.
4 Group B monitoring in water supply zones is required only where sodium hypochlorite is added after water has left the treatment works. In other circumstances, Group B monitoring is required at supply points.
5 To monitor for indicative dose (for radioactivity).
6 In the event that a single sample is taken in a year, a further sample should be taken if there is any change in relation to that supply that could affect the concentration of radionuclides in the water supply.
(1) Substances and parameters subject to monitoring
(2) Estimated population of water supply zone1
(3) Number of samples per year
Group A monitoring
Escherichia coli (E. coli)
< 100
≥ 100
4
12 per 5,000 population1
Coliform bacteria
Residual disinfectant
Aluminium
<100
100–4,999
5,000–9,999
10,000–29,999
30,000–49,999
50,000–79,999
80,000–100,000
2
4
12
24
36
52
76
Ammonium
Colony counts
Colour
Conductivity2
Hydrogen ion
Iron
Manganese
Nitrate3
Nitrite3
Odour
Taste
Turbidity
Group B monitoring
Aluminium
<100
100–4,999
5,000–100,000
1
4
8
Antimony
Arsenic
Benzene2
Benzo(a)pyrene
Boron2
Bromate4
Cadmium
Chromium
Clostridium perfringens (including spores)
Copper
Cyanide2
1,2 dichloroethane2
Enterococci
Fluoride2
Gross alpha25
Gross beta25
Iron
Lead
Manganese
Mercury2
Nickel
Nitrate3
Nitrite3
Pesticides and related
products2
Polycyclic aromatic hydrocarbons
Radon26
Selenium
Sodium
Trichloroethene/
Tetrachloroethene2
Tetrachloromethane2
Trihalomethanes
Chloride2
Sulphate2
Total organic carbon2
Tritium2
TABLE 3
Annual Sampling Frequencies: Treatment Works or Supply Points
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 2 and 3 to the Table below. This table sets out the annual sampling frequencies for all the substances and parameters in column 2 at treatment works or supply points. The frequencies are determined according to the volume of water supplied at each treatment works or supply point (column 3).
1 The water undertaker may use the number of inhabitants in a supply zone instead of the volume of water to determine the minimum frequency, assuming a water consumption of 200 l/day/capita.
2 The volumes are calculated as averages taken over a calendar year.
3 Sampling at treatment works when chloramination is practised.
4 Sampling at treatment works when chloramination is not practised.
5 Group B monitoring at supply points is required only where sodium hypochlorite is not added after water has left the treatment works. In other circumstances, Group B monitoring is required in water supply zones
6 To monitor for indicative dose (for radioactivity).
(1) Item
(2) Substances and parameters
(3) Volume of water supplied m3/d1
(4) Number of samples per year2
1
Escherichia coli (E. coli)
<20
20-1,999
2,000-5,999
6,000-11,999
≥ 12,000
4
52
104
208
365
2
Coliform bacteria
3
Colony counts
4
Nitrite3
5
Residual disinfectant
6
Turbidity
Group A monitoring
7
Conductivity
<20
20-999
1,000-1,999
2,000-5,999
6,000-9,999
10,000-15,999
16,000-32,999
33,000-49,999
50,000-67,999
68,000-84,999
85,000-101,999
102,000-119,999
120,000-241,999
242,000-484,999
485,000-728,999
2
4
12
24
36
52
104
156
208
260
312
365
730
1,460
2,190
Group A monitoring
8
Gross alpha6
<20
20-999
1,000-49,999
50,000-89,999
90,000-299,999
300,000-649,999
≥ 650,000
1
4
8
12
24
36
48
9
Gross beta6
10
Radon
11
Tritium
Group B monitoring
12
Benzene
<20
20-999
1,000-49,999
50,000-89,999
90,000-299,999
300,000-649,999
≥650,000
1
4
8
12
24
36
48
13
Boron
14
Bromate5
15
Clostridium perfringens (including spores)
16
Cyanide
17
1,2,dichloroethane
18
Fluoride
19
Mercury
20
Nitrite4
21
Pesticides and related products
22
Trichloroethene/
Tetrachloroethene
23
Tetrachloromethane
24
Chloride
25
Sulphate
26
Total Organic Carbon
27
Radon
28
Tritium
29
Gross alpha6
30
Gross beta6

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Source: https://www.legislation.gov.uk/nisr/2017/212/schedule/3/paragraph/1 (the official version)
Page: https://openlegislation.uk/water-supply-water-quality-regulations-northern-ireland-2017/schedule-3/paragraph-1
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.