The Water Supply (Water Quality) Regulations (Northern Ireland) 2017

Regulation 2 and 5

SCHEDULE 2 INDICATOR PARAMETERS

(1) Item	(2) Parameters	(3) Specification Concentration or Value (maximum unless otherwise stated) or State	(4) Units of Measurement	(5) Point of monitoring
(1) May be monitored from samples of water leaving treatment works or other supply point, as no significant change during distribution.
(2) The water should not be aggressive.
(3) Where radon concentrations exceed 1000Bq/l, remedial action must be carried out on radiological protection grounds without further consideration.
(4) Excluding tritium, potassium-40, radon and radon decay products.
(5) Elevated levels of tritium may indicate the presence of other artificial radionuclides. If the tritium concentration exceeds its parametric value, an analysis of the presence of other radionuclides is required.
(6) Where treatment to reduce the level of radionuclides in water intended for human consumption has been taken, monitoring must be carried out to ensure the continued efficacy of the treatment.
(7) If the gross alpha activity exceeds 0.1Bq/l or gross beta activity exceeds 1.0Bq/l, analysis for specific radionuclides is required.
1	Ammonium	0.50	mg/l	Consumers’ taps
2	Chloride(1) (2)	250	mg/l	Supply point
3	Clostridium perfringens (including spores)(1)	0	Number/100ml	Supply point
4	Coliform bacteria	0	Number/100ml	Consumers’ taps
5	Colony counts	No abnormal change	Number/1ml at 22°C Number/1ml at 37°C	Consumers’ taps, service reservoirs and treatment works
6	Conductivity(1) (2)	2500	µS/cm at 20°C	Supply point
7	Hydrogen ion(2)	9.5	pH units	Consumers’ taps
		6.5 (minimum)
8	Radon (for radioactivity)(1) (3) (6)	100	Bq/l	Supply point
9	Sulphate(1) (2)	250	mg/l	Supply point
10	Indicative dose (for radioactivity)(1) (4) (6) (7)	0.10	mSv	Supply point
11	Total organic carbon (TOC)(1)	No abnormal change	mg/l	Supply point
12	Tritium (for radioactivity)(1) (5) (6)	100	Bq/l	Supply point
13	Turbidity	1	NTU	Treatment works