The Private Water Supplies (Wales) Regulations 2010

Frequency of sampling

2.—(1) Sampling must be carried out at frequencies specified in Table 2.

Table 2

Sampling frequency for check monitoring

Volume m3/day	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)

(2) The local authority may reduce the frequency of sampling for a parameter to a frequency not less than half if—

(a) the local authority is of the opinion that the quality of water in the supply is unlikely to deteriorate;

(b) in the case of hydrogen ion the parameter has had a pH value that is not less than 6.5 and not more than 9.5; and

(c) in all other cases, in each of two successive years the results of samples taken for the purposes of monitoring the parameter in question are constant and significantly lower than the concentrations or values laid down in Schedule 1.

(3) The local authority may set a higher frequency for any parameter if it considers it appropriate taking into account the findings of any risk assessment, and in addition may monitor anything else identified in the risk assessment.

(4) Notwithstanding the provisions in sub-paragraph (2) above, there must be a minimum of 1 sample per year.