The Private Water Supplies (Wales) Regulations 2010

Regulation 9

SCHEDULE 2 Monitoring

PART 1 Check monitoring

Sampling

1.—(1) A local authority must undertake check monitoring in accordance with this Part.

(2) Check monitoring means sampling for each parameter listed in Table 1 in the circumstances listed in that table in order—

(a) to determine whether or not water complies with the concentrations or values in Schedule 1;

(b) to provide information on the organoleptic and microbiological quality of the water; and

(c) to establish the effectiveness of the treatment of the water, including disinfection.

Table 1

Check monitoring

Parameter	Circumstances
Aluminium	When used as flocculant or where the water originates from, or is influenced by, surface waters
Ammonium	In all supplies
Clostridium perfringens (including spores) waters	Where the water originates from, or is influenced by, surface
Coliform bacteria	In all supplies
Colony counts	In all supplies
Colour	In all supplies
Conductivity	In all supplies
Escherichia coli (E. coli)	In all supplies
Hydrogen ion concentration	In all supplies
Iron	When used as flocculant or where the water originates from, or is influenced by, surface waters
Manganese	Where the water originates from, or is influenced by, surface waters
Nitrate	When chloramination is practised
Nitrite	When chloramination is practised
Odour	In all supplies
Pseudomonas aeruginosa	Only in the case of water in bottles or containers
Taste	In all supplies
Turbidity	In all supplies

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.

PART 2 Audit monitoring

Sampling

3.—(1) A local authority must undertake audit monitoring in accordance with this Part.

(2) Audit monitoring means sampling for each parameter listed in Schedule 1 (other than parameters already being sampled under check monitoring) in order to provide information necessary to determine whether or not the private supply satisfies each concentration, value or state specified in that Schedule and, if disinfection is used, to check that disinfection by-products are kept as low as possible without compromising the disinfection.

(3) The local authority may, for such time as it may decide, exclude a parameter from the audit monitoring of a private supply—

(a) if it considers that the parameter in question is unlikely to be present in the supply or system at a concentration or value that poses a risk of the private supply failing to meet the concentration, value or state specified in Schedule 1 in respect of that parameter;

(b) taking into account the findings of any risk assessment; and

(c) taking into account any guidance issued by the Welsh Ministers.

(4) It may monitor anything else identified in the risk assessment.

Frequency of sampling

4.—(1) Sampling must be carried out at the frequencies specified in Table 3.

Table 3

Sampling frequency for audit monitoring

Volume m3/day	Sampling frequency per year
≤ 10	1
> 10 ≤ 3,300	2
> 3,300 ≤ 6,600	3
> 6,600 ≤ 10,000	4
> 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)

(2) 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.

PART 3 Minimum frequency for both check monitoring and audit monitoring for water put into bottles or containers

Volume1 of water produced in bottles or containers each day (m3)	Check monitoring number of samples per year	Audit monitoring number of samples per year
1 The volumes are calculated as averages taken over a calendar year.
≤ 10	1	1
>10≤60	12	1
> 60	1 for each 5 m3/day of the total volume (rounding up to the nearest multiple of 5 m3/day)	1 for each 100 m3/day of the total volume (rounding up to the nearest multiple of 100 m3/day)