The Water Supply (Water Quality) Regulations 2010

SCHEDULE 3 MONITORING

PART IV

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

Regulation 9

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 check monitoring	Estimated population of water supply zone	Reduced	Standard
Subject to check monitoring
a Where the population is not an exact multiple of 5,000, the population figure should be rounded up to the nearest multiple of 5,000.
b Sampling for these parameters may be within water supply zones or at supply points as specified in Table 3, subject to notes (iii) and (iv) below.
c Check monitoring in water supply zones is required only where chloramination is practised. In other circumstances audit monitoring is required.
d 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.
e To monitor for total indicative dose (for radioactivity).
E coli	<100		4
Coliform bacteria	≥100		12 per 5,000 populationa
Residual disinfectant
Aluminium	<100 100—4,999 5,000—9,999 10,000—29,999 30,000—49,999 50,000—79,999 80,000—100,000	1 2 6 12 18 26 38	2 4 12 24 36 52 76
Ammonium
Clostridium perfringens (including spores)b
Colony counts
Colour
Conductivityb
Hydrogen ion
Iron
Manganese
Nitrate c
Nitrite c
Odour
Taste
Turbidity
Subject to audit monitoring
Aluminium	<100 100—4,999 5,000—100,000		1 4 8
Antimony
Arsenic
Benzeneb
Benzo(a)pyrene
Boronb
Bromate d
Cadmium
Chromium
Clostridium perfringens (including spores)
Copper
Cyanideb
1,2 dichloroethaneb
Enterococci
Fluorideb
Iron
Lead
Manganese
Mercuryb
Nickel
Nitrate c
Nitrite c
Pesticides and related products b
Polycyclic aromatic hydrocarbons
Selenium
Sodium
Trichloroethene /Tetrachloroetheneb
Tetrachloromethaneb
Trihalomethanes
Chlorideb
Sulphateb
Total organic carbonb
Tritiumb
Gross alpha b e
Gross beta b e

Regulation 9

Table 3 Annual Sampling Frequencies: Treatment Works or Supply Points

Note 1: Sampling is at treatment works for the substances and parameters shown in column (1) of the Table as items (1) to (6) and at supply points for the other substances and parameters, except nitrate subject to footnotes (ii) and (ii)(a) 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
a Sampling at treatment works when chloramination is practised.
b Check monitoring is required only in respect of surface waters (see regulation 6(2) and Table 1 in Schedule 3).
c 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.
d Sampling at treatment works when chloramination is not practised.
e To monitor for total indicative dose (for radioactivity).
1.	E Coli	<20 20—1,999 2,000—5,999 6,000—11,999 ≥12,000	— 12 52 104 104	4 52 104 208 365
2.	Calliform bacteria
3.	Colony counts
4.	Nitrite a
5.	Residual disinfectant
6.	Turbidity
Subject to check monitoring
7.	Clostridium perfringens b	<20 20—999 1,000—1,999 2,000—5,999 6,000—9,999 10,000—15,999 16,000—32,999 33,000—49,999 50,000—67,999 68,000—84,999 85,000—101,999 102,000—119,999 120,000—241,999 242,000—484,999 485,000—728,999	— 2 6 12 18 26 52 78 104 130 156 183 365 730 1,095	2 4 12 24 36 52 104 156 208 260 312 365 730 1,460 2,190
8.	Conductivity
Subject to audit monitoring
9.	Benzene	<20 20—999 1,000—49,999 50,000—89,999 90,000—299,999 300,000—649,000 ≥650,000	1 4 8 12 24 36 48
10.	Boron
11.	Bromate c
11A.	Clostridium perfringens (including spores)
12.	Cyanide
13.	1,2 dichloroethane
14.	Fluoride
15.	Mercury
16.	Nitrite d
17.	Pesticides and Related products
18.	Trichloroethene
	Tetrachloroethene
19.	Tetrachloromethane
20.	Chloride
21.	Sulphate
22.	Total organic carbon
23.	Tritium
24.	Gross alpha e
25.	Gross beta e