The Water Supply (Water Quality) Regulations 2016

Regulation 6

SCHEDULE 3 Monitoring

Table 1

Parameters and circumstances for check monitoring

(1)	(2)	(3)
Item	Parameter	Circumstances
1.	Aluminium	When used as flocculant or where the water originates from, or is influenced by, surface waters
2.	Ammonium
3.	Clostridium perfringens (including spores)	Where the water originates from, or is influenced by, surface waters
4.	Coliform bacteria
5.	Colony counts
6.	Colour
7.	Conductivity
8.	Escherichia coli (E. coli)
9.	Hydrogen ion
10.	Iron	When used as flocculant or where the water originates from, or is influenced by, surface waters
11.	Manganese	Where the water originates from, or is influenced by, surface waters
12.	Nitrate	When chloramination is practised
13.	Nitrite	When chloramination is practised
14.	Odour
15.	Taste
16.	Turbidity

Table 2

Annual sampling frequencies: water supply zones

Note: 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). The number of samples is either the standard number in column 4 or the reduced number in column 3 (if one is given). Regulation 9 provides for the circumstances in which the reduced number of samples may be taken.

(1)		(2)	(3)	(4)
Substances and parameters subject to monitoring		Estimated population of water supply zone	Reduced	Standard
(i) Where the population is not an exact multiple of 5,000, the population figure must be rounded up to the nearest multiple of 5,000.
(ii) Sampling for these parameters may be within water supply zones or at supply points as specified in Table 3, subject to footnotes (iii) and (iv) below.
(iii) Check monitoring in water supply zones is required only where chloramination is practised. In other circumstances audit monitoring is required.
(iv) Audit monitoring in water supply zones is required only where sodium hypochlorite is added after water has left the treatment works. In other circumstances, audit monitoring is required at supply points.
(v) To monitor for indicative dose.
(vi) 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.
Subject to check monitoring
E. coli	<100			4
Coliform bacteria	≥100			12 per 5,000
Residual disinfectant				Population(i)
Aluminium	<100		1	2
Ammonium	100-4,999		2	4
Clostridium perfringens	5,000-9,999		6	12
(including spores)	10,000-29,999		12	24
Colony counts	30,000-49,999		18	36
Colour	50,000-79,999		26	52
Conductivity(ii)	80,000-100,000		38	76
Hydrogen ion
Iron
Manganese
Nitrate(iii)
Nitrite
Odour
Taste
Turbidity
Subject to audit monitoring
Aluminium	<100			1
Antimony	100-4,999			4
Arsenic	5,000-100,000			8
Benzene(ii)
Benzo(a)pyrene
Boron(ii)
Bromate(iv)
Cadmium
Chromium
Clostridium perfringens
(including spores)
Copper
Cyanide(ii)
1,2 dichloroethane(ii)
Enterococci
Fluoride(ii)
Gross alpha(ii) (v) (vi)
Gross beta(ii) (v) (vi)
Iron
Lead
Manganese
Mercury(ii)
Nickel
Nitrate(iii)
Nitrite(iii)
Pesticides and related products(ii)
Polycyclic aromatic hydrocarbons
Radon(ii) (vi)
Selenium
Sodium
Trichloroethene
Tetrachloroethene(ii)
Tetrachloromethane(ii)
Trihalomethanes
Chloride(ii)
Sulphate(ii)
Total organic carbon(ii)
Tritium(ii) (vi)

Table 3

Annual sampling frequencies: treatment works or supply points

Note 1: Sampling is at treatment works for the substances and parameters in column 2 of the Table (items (1) to (6)) and at supply points for the other substances and parameters, except nitrite, subject to footnotes (i) and (iv) to the Table below.

Note 2: 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). The number of samples is either the standard number in column 5 or the reduced number in column 4 (if one is given). Regulation 9 provides for the circumstances in which the reduced number of samples may be taken.

(1)	(2)	(3)	(4)	(5)
Item	Substances and parameters	Volume of water supplied m3/d	Reduced	Standard
(i) Sampling is at treatment works when chloramination is practised.
(ii) Check monitoring is required only in respect of surface waters (see regulation 6(2) and Table 1 in Schedule 3).
(iii) Audit monitoring at supply points is required only where sodium hypochlorite is not added after water has left the treatment works. In other circumstances, audit monitoring is required in water supply zones.
(iv) Sampling at treatment works when chloramination is not practised.
(v) To monitor for indicative dose.
1.	E. coli	<20	-	4
2.	Coliform bacteria	20–1,999	12	52
3.	Colony counts	2,000–5,999	52	104
4.	Nitrite(i)	6,000–11,999	104	208
5.	Residual disinfectant	≥12,000	104	365
6.	Turbidity
Subject to check monitoring
7.	Clostridium perfringens(ii)	<20	-	2
8.	Conductivity	20–999	2	4
		1,000–1,999	6	12
		2,000-5,999	12	24
		6,000-9,999	18	36
		10,000-15,999	26	52
		16,000-32,999	52	104
		33,000-49,999	78	156
		50,000-67,999	104	208
		68,000-84,999	130	260
		85,000-101,999	156	312
		102,000-119,999	183	365
		120,000-241,999	365	730
		242,000–484,999	730	1,460
		485,000–728,999	1,095	2,190
Subject to audit monitoring
9.	Benzene	<20		1
10.	Boron	20–999		4
11.	Bromate(iii)	1,000–49,999		8
12.	Clostridium	50,000–89,999		12
	Perfringens (including spores)	90,000–299,999		24
13.	Cyanide	300,000–649,999		36
14.	1,2 dichloroethane	≥650,000		48
15.	Fluoride
16.	Indicative dose
17.	Mercury
18.	Nitrite(iv)
19.	Pesticides and related products
20.	Radon
21.	Trichloroethene/
	Tetrachloroethene
22.	Tetrachloromethane
23.	Chloride
24.	Sulphate
25.	Total organic carbon
26.	Tritium
27.	Gross alpha(v)
28.	Gross beta(v)