The Water Supply (Water Quality) (Scotland) Regulations 2001

TABLE 4 ANNUAL SAMPLING FREQUENCIES: WATER TREATMENT WORKS

(1)	(2)	(3)	(4)	(5)
Item	Substances and parameters subject to check monitoring	Volume of water supplied m3/d	Reduced	Standard
Notes:
(i) check monitoring at treatment works is required only when chloramination is practised. In other circumstances, audit monitoring is required.
1.	E. coli	<20		4
2.	Coliform bacteria	20 – 1,999	12	52
3.	Colony counts	2,000 – 5,999	52	104
4.	Residual disinfectant	6,000 – 11,999	104	208
		≥12,000	104	365
5.	Nitrite(i)	<20		2
6.	Turbidity	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
	Substances and parameters subject to audit monitoring
7.	Nitrite(i)	<20		1
		20 – 999		4
		1,000 – 49,999		8
		50,000 – 89,999		12
		90,000 – 299,999		24
		300,000 – 649,999		36
		>650,000		48