The Water Supply (Water Quality) Regulations 2001

Part IV

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

(1)	(2)	(3)	(4)
Substances and parameters subject to check monitoring	Estimated population of water supply zone	Reduced	Standard
Notes:
* Sampling for these parameters may be within water supply zones or at supply points as specified in Table 3, subject to notes (ii) and (iii) below.
(i) 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.
(ii) Check monitoring in water supply zones is required only where chloramination is practised. In other circumstances audit monitoring is required.
(iii) 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.
(iv) To monitor for total indicative dose (for radioactivity).
E. coli
Coliform bacteria	<100		4
Residual disinfectant	≥100		12 per 5,000 population(i)
Aluminium
Ammonium
Clostridium perfringens (including spores)*	<100	1	2
	100—4,999	2	4
	5,000—9,999	6	12
Colony counts	10,000—29,999	12	24
Colour	30,000—49,999	18	36
Conductivity*	50,000—79,999	26	52
Hydrogen ion	80,000—100,000	38	76
Iron
Manganese
Nitrate(ii)
Nitrite(ii)
Odour
Taste
Turbidity
Parameters subject to audit monitoring
Aluminium
Antimony
Arsenic
Benzene*	<100		1
Benzo(a)pyrene	100—4,999		4
Boron*	5,000—100,000		8
Bromate(iii)
Cadmium
Chromium
Copper
Cyanide*
1,2 dichloroethane*
Enterococci
Fluoride*
Iron
Lead
Manganese
Mercury*
Nickel
Nitrate (ii)
Nitrite (ii)
Pesticides and related products*
Polycyclic aromatic	<100		1
hydrocarbons	100—4,999		4
Selenium	5,000—100,000		8
Sodium
Trichloroethene
/Tetrachloroethene*
Tetrachloromethane*
Trihalomethanes
Chloride*
Sulphate*
Total organic carbon*
Tritium*
Gross alpha* (iv)
Gross beta* (iv)

TABLE 3 ANNUAL SAMPLING FREQUENCIES: TREATMENT WORKS OR SUPPLY POINTS*

(1)	(2)	(3)	(4)	(5)
Item	Substances and parameters	Volume of water supplied m3/d	Reduced	Standard
Notes:
* 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 nitrite, subject to notes (ii) and (iii) below.
(i) Check monitoring is required only in respect of surface waters (see regulation 6(2) and Table 1 in Schedule 3).
(ii) Sampling at treatment works when chloramination is practised.
(ii) Sampling at treatment works when chloramination is not practised.
(iv) 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.
(v) To monitor for total indicative dose (for radioactivity).
1.	E. Coli	<20		4
2.	Coliform bacteria	20—1,999	12	52
3.	Colony counts	2,000—5,999	52	104
4.	Nitrite (ii)	6,000—11,999	104	208
5.	Residual disinfectant	≥12,000	104	365
6.	Turbidity
Subject to check monitoring
7.	Clostridium perfringens(i)	<20		2
		20 — 999	2	4
8.	Conductivity	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
10.	Boron
11.	Bromate (iv)
12.	Cyanide
13.	1,2 dichloroethane
14.	Fluoride
15.	Mercury	<20		1
16.	Nitrite (ii)	20—999		4
17.	Pesticides and Related products	1,000—49,999	8
		50,000—89,999	12
		90,000—299,999	24
		300,000—649,000	36
18.	Trichloroethene ) Tetrachloroethene)	≥650,000	48
19.	Tetrachloromethane
20.	Chloride
21.	Sulphate
22.	Total organic carbon
23.	Tritium
24.	Gross alpha (v)
25.	Gross beta (v)