# The Private Water Supplies Regulations (Northern Ireland) 2017, Paragraph 2


(1) Sampling for a Group A parameter which is not a radioactive substance must be undertaken at the frequencies specified in Table 2 for those parameters.
(2) Sampling for a Group A parameter which is a radioactive substance must be undertaken at the frequencies specified in Table 3 for those parameters.
TABLE 2
Sampling frequency of sampling for Group A parameters (non radioactive substances)
Volume m3/day(calculated as averages taken over a calendar year)
Sampling frequency per year
≤10
1
> 10 ≤ 100
2
> 100 ≤ 1,000
4
> 1,000 ≤ 2,000
10
> 2,000 ≤ 3,000
13
> 3,000 ≤ 4,000
16
> 4,000 ≤ 5,000
19
> 5,000 ≤ 6,000
22
> 6,000 ≤ 7,000
25
> 7,000 ≤ 8,000
28
> 8,000 ≤ 9,000
31
> 9,000 ≤ 10,000
34
> 10,000
4 + 3 for each 1,000 m3/day of the total volume (rounding up to the nearest multiple of 1,000 m3/day)
TABLE 3
Minimum frequency of sampling for Group A monitoring radioactive substances
Volume m3 /day (calculated as averages taken over a calendar year)
Sampling frequency per year
≤ 1000
1
> 1000 ≤ 10,000
1 + 1 for each 3,300 m3/day of the total volume (rounding up to the nearest multiple of 3,300 m3/day)
> 10,000 ≤ 100,000
3 + 1 for each 10,000 m3/day of the total volume (rounding up to the nearest multiple of 10,000 m3/day)
> 100,000
10 + 1 for each 25,000 m3/day of the total volume (rounding up to the nearest multiple of 25,000 m3/day)

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Source: https://www.legislation.gov.uk/nisr/2017/211/schedule/3/paragraph/2 (the official version)
Page: https://openlegislation.uk/private-water-supplies-regulations-northern-ireland-2017/schedule-3/paragraph-2
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.