# The Surface Waters (Abstraction for Drinking Water) (Classification) Regulations (Northern Ireland) 1996, Schedule 1: Characteristics of Surface Water intended for the Abstraction of Drinking Water

Extent: N.I.
Status: prospective

No in Annex II to 75/440/EEC
Parameters
DW1
DW2
DW3
G
I
G
I
G
I
(1) The values given are upper limits set in relation to the mean annual temperature (high and low).
(2) This parameter has been included to satisfy the ecological requirements of certain types of environment.
* See regulation 6(1)(d)
(O) See regulation 6(1)(b)
1
pH
6.5 to 8.5
5.5 to 9
5.5 to 9
2
Coloration (after simple filtration)
mg/l Pt scale
10
20
50
100
50
200
3
Total suspended solids
mg/l SS
25
4
Temperature
°C
22
25
22
25
22
25
5
Conductivity
μs/cm−1 at 20°C
1,000
1,000
1,000
6
Odour
(dilution factor at 25°C)
3
10
20
7
Nitrates
mg/l NO3
25
50
50
50
8
Fluorides
mg/l F
0.7 to 1
1.5
0.7 to 1.7
0.7 to 1.7
10
Dissolved iron
mg/l Fe
0.1
0.3
1
2
1
11
Manganese
mg/l Mn
0.05
0.1
1
12
Copper
mg/l Cu
0.02
0.05
0.05
1
13
Zinc
mg/l Zn
0.5
3
1
5
1
5
14
Boron
mg/l B
1
1
1
19
Arsenic
mg/l As
0.01
0.05
0.05
0.05
0.1
20
Cadmium
mg/l Cd
0.001
0.005
0.001
0.005
0.001
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/1 Hg
0.0005
0.001
0.0005
0.001
0.0005
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
150
250
150
250
150
250
28
Chlorides
mg/l Cl
200
200
200
29
Surfactants (reacting with methyl blue)
mg/l (lauryl sulphate)
0.2
0.2
0.5
30
Phosphates
mg/l P2O5
0.4
0.7
0.7
31
Phenols (phenol index) paranitraniline 4 amino-antipyrine
mg/l C6H5OH
0.001
0.001
0.005
0.01
0.1
32
Dissolved or emulsified hydrocarbons (after extraction by petroleum ether)
mg/l
0.05
0.2
0.5
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
35
Chemical oxygen demand (COD)
mg/l O2
30
36
Dissolved oxygen saturation rate
% O2
>70
>50
>30
37
Biochemical oxygen demand (BOD5) (at 20°C without nitrification)
mg/l O2
<3
<5
<7
38
Nitrogen by Kjeldahl method (except NO3)
mg/l N
1
2
3
39
Ammonia
mg/l NH4
0.05
1
1.5
2
4
40
Substances extractable with chloroform
mg/l SEC
0.1
0.2
0.5
43
Total coliforms 37°C
/100 ml
50
5,000
50,000
44
Faecal coliforms
/100 ml
20
2,000
20,000
45
Faecal streptococci
/100 ml
20
1,000
10,000
46
Salmonella
Not Present in 5,000 ml
Not Present in 1,000 ml

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Source: https://www.legislation.gov.uk/nisr/1996/603/schedule/1 (the official version)
Page: https://openlegislation.uk/surface-waters-abstraction-for-drinking-water-classification-regulations-northern-ireland-1996/schedule-1
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.