# The Private Water Supplies Regulations (Northern Ireland) 2017, Part 2: Indicator Parameters


TABLE C
Prescribed concentrations and values
1 The water must not be aggressive.
2 Excluding tritium, potassium-40, radon and radon decay products.
3 Where treatment to reduce the level of radionuclides in water intended for human consumption has been taken, monitoring must be carried out under Schedule 3 Part 1 to ensure efficacy of treatment.
4 If the gross alpha activity exceeds 0.1Bq/l or the gross beta activity exceeds 1.0Bq/l analysis for specific radionuclides is required.
5 If tritium concentration exceeds its parametric value an investigation (which may include analysis) of the presence of other artificial radionuclides must be carried out.
6 Remedial action is deemed to be justified on radiological ground without further consideration, where radon exceeds 1,000Bq/l.
7 Only in the case of surface water treatment where the parametric value should be strived for the water ex-treatment works.
Parameter
Parametric value
Unit
Ammonium
0.50
mg/l
Chloride1
250
mg/l
Clostridium perfringens
(including spores)
0
number/100 ml
Coliform bacteria
0
Number/100ml
Colony count 22 °C
No abnormal change
number/1 ml
Conductivity1
2500
μS/cm at 20 °C
Hydrogen ion concentration1
≥ 6.5 and ≤ 9.5
pH units
Indicative Dose (for radioactivity)234
0.10
mSv
Sulphate1
250
mg/l
Radon (for radioactivity)36
100
Bq/l
Total organic carbon
No abnormal change
mg/l
Tritium (for radioactivity)35
100
Bq/l
Turbidity7
1
NTU

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Source: https://www.legislation.gov.uk/nisr/2017/211/schedule/1/part/2 (the official version)
Page: https://openlegislation.uk/private-water-supplies-regulations-northern-ireland-2017/schedule-1/part-2
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.