# The Water Supply (Water Quality) Regulations 2018, Schedule 2: INDICATOR PARAMETERS


1 The water should not be aggressive.
2 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.
3 Remedial action may be taken by the Welsh Ministers on radiological protection grounds without further consideration and deemed to be justified where radon concentrates exceed 1,000 Bq/1.
4 If tritium concentration exceeds its parametric value, an investigation (which may include analysis) of the presence of artificial radionuclides is required.
5 May be monitored from samples of water leaving treatment works or other supply point, as no significant change during distribution.
Item Parameters
Specification
Concentration or Value (maximum unless otherwise stated) or State
Units of Measurement
Point of compliance
1
Ammonium
0.50
μgAl/l
Consumers' taps
2
Chloride 1
250
mgCl/l
Supply point 5
3
Clostridium perfringens (including spores)
0
Number/100 ml
Supply point 5
4
Coliform bacteria
0
Number/100 ml
Consumers' taps
5
Colony counts
No abnormal change
Number/1 ml at 22°C
Consumers' taps, service reservoirs and treatment works
6
Conductivity 1
2500
μS/cm at 20°C
Supply point 5
7
Hydrogen ion
9.5
pHvalue
Consumers' taps
6.5 (minimum)
8
Indicative dose 2
0.10
mSv
Supply point 5
(a) gross alpha
0.1
Bq/l
Supply point 5
(b) gross beta
1
Bq/l
Supply point 5
9
Radon 3
100
Bq/l
Supply point
10
Sulphate 1
250
mgSO4/l
Supply point 5
11
Total organic carbon (TOC)
No abnormal change
mgC/l
Supply point
12
Tritium (for radioactivity) 4
100
Bq/l
Supply point
13
Turbidity
1
NTU
Treatment works
Notes:

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Source: https://www.legislation.gov.uk/wsi/2018/647/schedule/2 (the official version)
Page: https://openlegislation.uk/water-supply-water-quality-regulations-2018/schedule-2
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.