# The Surface Waters (Abstraction for Drinking Water) (Classification) Regulations 1996, Schedule 1: CRITERIA FOR CLASSIFICATION OF WATERS


The limits set out below are maxima
No. in Annex II to 75/440/EEC
Parameters
Units
Limits
DW1
DW2
DW3
(O) See regulation 4(1)(b).
* See regulation 4(1)(d).
2
Coloration (after simple filtration)
mg/1 Pt Scale
20
100
200
4
Temperature
°C
25
25
25
7
Nitrates
mg/l NO3
50
50
50
8
Fluorides
mg/l F
1.5
10
Dissolved iron
mg/l Fe
0.3
2
12
Copper
mg/l Cu
0.05
13
Zinc
mg/l Zn
3
5
5
19
Arsenic
mg/l As
0.05
0.05
0.1
20
Cadmium
mg/l Cd
0.005
0.005
0.005
21
Total chromium
mg/l Cr
0.05
0.05
0.05
22
Lead
mg/l Pb
0.05
0.05
0.05
23
Selenium
mg/l Se
0.01
0.01
0.01
24
Mercury
mg/l Hg
0.001
0.001
0.001
25
Barium
mg/l Ba
0.1
1
1
26
Cyanide
mg/l CN
0.05
0.05
0.05
27
Sulphates
mg/l SO4
250
250
250
31
Phenols (phenol index) paranitraniline 4-aminoantipyrine
mg/l C6H5OH
0.001
0.005
0.1
32
Dissolved or emulsified hydrocarbons
mg/l
0.05
0.2
1
33
Polycyclic aromatic hydrocarbons
mg/l
0.0002
0.0002
0.001
34
Total pesticides (parathion, hexachlorocyclohexane, dieldrin)
mg/l
0.001
0.0025
0.005
39
Ammonium
mg/l NH4
1.5
4

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Source: https://www.legislation.gov.uk/uksi/1996/3001/schedule/1 (the official version)
Page: https://openlegislation.uk/surface-waters-abstraction-for-drinking-water-classification-regulations-1996/schedule-1
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.