# The Surface Waters (Abstraction for Drinking Water) (Classification) (Scotland) Regulations 1996, Schedule 2: GUIDELINE VALUES


No in Annex II to 75/440/EEC
Parameters
DW1
DW2
DW3
1The value given is an upper limit set in relation to the mean annual temperature (high and low).
2This parameter has been included to satisfy the ecological requirements of certain types of environment.
*See regulation 8(1)(c)
1
pH
6.5 to 8.5
5.5 to 9
5.5 to 9
2
Coloration (after simple filtration)
mg/1 Pt Scale
10
50
50
3
Total suspended solids
mg/1 SS
25
4
Temperature
°C
22
22
22
5
Conductivity at 20°C
μs/cm
1000
1000
1000
6
Odour
dilution factor at 25°C
3
10
20
7
Nitrates
mg/1 NO3
25
8
Fluorides
mg/1 F
0.7 to 1
0.7 to 1.7
0.7 to 1.7
10
Dissolved iron
mg/1 Fe
0.1
1
1
11
Manganese
mg/1 Mn
0.05
0.1
1
12
Copper
mg/1 Cu
0.02
0.05
1
13
Zinc
mg/1 Zn
0.5
1
1
14
Boron
mg/1 B
1
1
1
19
Arsenic
mg/1 As
0.01
0.05
20
Cadmium
mg/1 Cd
0.001
0.001
0.001
24
Mercury
mg/1 Hg
0.0005
0.0005
0.0005
27
Sulphates
mg/1 SO4
150
150
150
28
Chlorides
mg/1 Cl
200
200
200
29
Surfactants (reacting with methyl blue)
mg/1 (laurylsulphate)
0.2
0.2
0.5
30
Phosphates
mg/1 P2O5
0.4
0.7
0.7
31
Phenols (phenol index) paranitroaniline 4-aminoantipyrine
mg/1 C6H5OH
0.001
0.01
32
Dissolved or emulsified hydro carbons (after extraction by petroleum ether)
mg/1
0.5
35
Chemical oxygen demand (COD)
mg/1 O2
30
36
Dissolved oxygen saturation rate
% O2
>70
>50
>30
37
Biochemical oxygen demand (BOD5) (at 20°C without nitrification)
mg/1 O2
<3
<5
<7
38
Nitrogen Kjeldahl method (except NO3)
mg/1 N
1
2
3
39
Ammonia
mg/1 NH4
0.05
1
2
40
Substances extractable with chloroform
mg/1 SEC
0.1
0.2
0.5
43
Total coliforms 37°C
/100ml
50
5,000
50,000
44
Faecal coliforms
/100ml
20
2,000
20,000
45
Faecal streptococci
/100ml
20
1,000
10,000
46
Salmonella
Not present in 5,000ml
Not present in 1,000ml

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Source: https://www.legislation.gov.uk/uksi/1996/3047/schedule/2 (the official version)
Page: https://openlegislation.uk/surface-waters-abstraction-for-drinking-water-classification-scotland-regulations-1996/schedule-2
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.