The Private Water Supplies (Wales) Regulations 2017

Regulations 2, 9, 18 and 26

SCHEDULE 2 Monitoring

PART 1 Monitoring for Group A parameters

Sampling

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

(2) “Monitoring for Group A parameters” means sampling for each parameter listed in column 1 of Table 1 in the circumstances listed in the corresponding entry for that parameter in column 2 of that Table, in order to—

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

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

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

Table 1

Group A parameters

Parameter	Circumstances
Aluminium	If used as a water treatment chemical
Ammonium	If chloramination is used
Clostridium perfringens (including spores)	Where the water originates from, or is influenced by, surface waters
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	If used as a water treatment chemical
Manganese	Where the water originates from, or is influenced by, surface waters
Nitrate	If chloramination is used
Nitrite	If chloramination is used
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.  Sampling for Group A parameters must be carried out at frequencies specified in Table 2.

Table 2

Sampling frequency for Group A parameters

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)

PART 2 Monitoring for Group B parameters

Sampling

3.—(1) A local authority must undertake monitoring for Group B parameters in accordance with this Part.

(2) “Monitoring for Group B parameters” means sampling for each parameter listed in Part 1 or 2 of Schedule 1 (other than Group A parameters already being sampled under Part 1 of this Schedule)—

(a) in order to provide information necessary to determine whether or not the private water supply satisfies each concentration, value or state specified in either of those Parts of that Schedule; and

(b) if disinfection is used, to check that disinfection by-products are kept as low as possible without compromising the effectiveness of disinfection.

Frequency of sampling

4.  Sampling for Group B parameters must be carried out at the frequencies specified in Table 3.

Table 3

Sampling frequency for Group B parameters

Volume m3/day	Sampling frequency per year
≤10	1
˃ 10 ≤ 3,300	2
˃ 3,300 ≤ 6,600	3
˃ 6,600 ≤ 100,00	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)

PART 3 Minimum frequency for both monitoring for Group A parameters and monitoring for Group B parameters for water put into bottles or containers

Volumea of water produced in bottles or containers each day (m3)	Monitoring for Group A parameters: number of samples per year	Monitoring for Group B parameters: number of samples per 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)
a The volumes are calculated as averages taken over a calendar year.

PART 4 Variation of monitoring requirements for Group A and Group B parameters

Variation of sampling frequency

5.—(1) A local authority may reduce the sampling frequencies required for a parameter (other than for Escherichia coli (E. coli)) under Part 1 or 2 of this Schedule provided that—

(a) the results from samples taken in respect of that parameter collected at regular intervals over the preceding 3 years are all at less than 60% of the parametric value;

(b) the results of a risk assessment are considered, and that risk assessment indicates that no factor can be reasonably anticipated to be likely to cause deterioration of the quality of the water for human consumption;

(c) data collected in the course of discharging its monitoring obligations under this Part are taken into account; and

(d) at least one sample is taken per year.

(2) A local authority may set a higher frequency for any parameter if it considers it appropriate taking into account the findings of any risk assessment.

Variation of parameters

6.—(1) A local authority may cease to monitor a parameter (other than Escherichia coli (E. coli)) otherwise required to be monitored under Part 1 or 2 of this Schedule provided that—

(a) the results from samples taken in respect of that parameter collected at regular intervals over the preceding 3 years are all at less than 30% of the parametric value;

(b) the results of a risk assessment are considered, and that risk assessment indicates that no factor can be reasonably anticipated to be likely to cause deterioration of the quality of the water for human consumption; and

(c) data collected in the course of discharging its monitoring obligations under this Part are taken into account.

(2) A local authority may monitor for other properties, elements, organisms or substances not included as a parameter if it considers it appropriate taking into account the findings of any risk assessment.