
1996 No. 603
WATER AND SEWERAGE
The Surface Waters (Abstraction for Drinking Water) (Classification) Regulations (Northern Ireland) 1996
Made 20th December 1996
Coming into operation 20th February 1997
The Department of the Environment, in exercise of the powers conferred on it by section 4B of the Water Act (Northern Ireland) 1972 and now vested in it, section 56B of the Water and Sewerage Services Order (Northern Ireland) Order 1973 and, being a department designated for the purposes of section 2(2) of the European Communities Act 1972 in relation to measures relating to the prevention, reduction and elimination of pollution of water, in exercise of the powers conferred on it by that section and of every other power enabling it in that behalf, hereby makes the following Regulations:
Citation and commencement
1 
These Regulations may be cited as the Surface Waters (Abstraction for Drinking Water) (Classification) Regulations (Northern Ireland) 1996 and shall come into operation on 20th February 1997.
Interpretation
2 

(1) In these Regulations—
 “the Department” means the Department of the Environment; and
 “pollution control functions” means the Department’s functions under or by virtue of the following statutory provisions, that is to say—
(a) the Water Act (Northern Ireland) 1972;
(b) the Water and Sewerage Services (Northern Ireland) Order 1973;
(c) regulations made by virtue of section 2(2) of the European Communities Act 1972, to the extent that the regulations relate to pollution of water.
(2) Expressions used in these Regulations which are also used in Directive 75/440/EEC (quality required of surface waters used for abstraction of drinking water) or Directive 79/869/EEC (methods of measurement and frequency of sampling and analysis of such waters) shall have the same meaning as in those Directives.
(3) In these Regulations any reference to the supply of water as drinking water shall be taken to be a reference to the supply of that water as drinking water after it has undergone purification treatment.
(4) The Interpretation Act (Northern Ireland) 1954 shall apply to these Regulations as it applies to a Measure of the Northern Ireland Assembly.
Classification of waters
3 
The classifications DW1, DW2 and DW3 and the criteria for those classifications set out in Schedule 1 shall apply for classifying waters by reference to their suitability for abstraction by the Department for supply (after treatment) as drinking water.
Compliance with relevant limits
4 

(1) Subject to paragraphs (2) and (3), any waters classified under these Regulations shall be treated in any year as complying with the limits specified in column I of Schedule 1 for waters of the relevant class in relation to a parameter if—
(a) 95 per cent of the samples taken in relation to those waters in accordance with regulation 7 comply with the limits specified in column I of Schedule 1;
(b) none of the samples exceeds the limit by more than 50 per cent;
(c) there is no associated danger to public health where any of the samples exceeds the limit; and
(d) there have been no occasions on which consecutive samples so taken at statistically suitable intervals exceed the limit.
(2) Non-compliant samples shall be ignored for the purposes of paragraph (1) if they are the result of a flood, natural disaster or abnormal weather conditions.
(3) Paragraph 1(b) shall not apply in the case of any standard adopted by the Department in relation to temperature.
Guideline values and no deterioration principle
5 
In discharging its pollution control functions in relation to any waters classified under these Regulations, the Department shall—
(a) endeavour to respect the guideline values specified in column G of Schedule 1 for waters of the relevant class;
(b) act in accordance with the principle that implementation of measures taken pursuant to Directive 75/440/EEC may under no circumstances lead directly or indirectly to deterioration of the current quality of surface water.
Compliance with standards
6 

(1) Subject to paragraphs (2) and (3), any waters classified under these Regulations shall be treated as complying with any standard in relation to any parameter adopted by the Department as a result of regulation 5 in relation to those waters if—
(a) 90 per cent of the samples taken in relation to the waters in accordance with regulation 5 comply with the standard;
(b) none of the samples fails the standard by more than 50 per cent;
(c) there is no associated danger to public health where any of the samples fails to comply with the standard; and
(d) there have been no occasions on which consecutive samples so taken at statistically suitable intervals fail to comply with the standard.
(2) Non-compliant samples shall be ignored for the purposes of paragraph (1) if they are the result of a flood, natural disaster or abnormal weather conditions.
(3) Paragraph 1(b) shall not apply in the case of any standard adopted by the Department in relation to temperature, pH, dissolved oxygen and microbiological parameters
Waivers
7 

(1) Subject to the provisions of this regulation, the Department may waive any requirement to comply with the relevant limit value for any parameter in relation to waters classified under these Regulations or any standard adopted as a result of regulation 5 for any parameter in relation to any water classified under these Regulations if it considers it appropriate to do so—
(a) as a result of any flood or other natural disaster;
(b) in the case of any parameter marked (O) in Schedule 1, as a result of exceptional meteorological or geographical conditions;
(c) where the waters undergo natural enrichment in certain substances as a result of which the waters would exceed the relevant limit value for that parameter;
(d) in the case of a shallow lake or virtually stagnant surface water, for parameters marked with an asterisk in Schedule 1.
(2) The Department shall not waive any requirement if that would result in a danger to public health.
(3) Paragraph (1)(d) shall only apply in the case of a shallow lake where—
(a) the depth of the lake does not exceed 20 metres;
(b) the exchange of water is slower than a year; and
(c) waste water is not discharged into the lake.
(4) In this regulation “natural enrichment” means a process whereby without human intervention a given body of water receives from the soil certain substances contained therein.
Sampling and analysis
8 

(1) Subject to Regulation 9, the Department shall ensure that waters classified under these Regulations are sampled and samples are analysed in accordance with paragraphs (2) to (5).
(2) Samples shall always be taken at the same sampling point at times when water is being abstracted by the Department for supply as drinking water and the sampling point chosen by the Department must be—
(a) at the place where water is abstracted before being sent for purification treatment; and
(b) so situated that samples taken at that point are representative of the quality of the water at that place.
(3) Samples shall be analysed for compliance with the parameters listed in Part I of Schedule 2 for the relevant class of waters using methods of measurement which are at least as reliable as those specified in that Part and respect the values shown in that Part for limits of detection, precision and accuracy.
(4) Sampling and analysis shall be carried out at the frequency fixed by the Department in relation to the sampling point for those waters for each parameter listed in Schedule 1 and, in fixing the frequency, the Department shall ensure that—
(a) sampling is carried out at regular intervals;
(b) the annual frequency of sampling and analysis for each parameter is not less than that specified in Part II of Schedule 2 for the relevant class of waters; and
(c) sampling is as far as possible spread over the year so as to give a representative picture of the quality of the water.
(5) The containers used for samples, the agents or methods used to preserve part of the sample for the analysis of one or more parameters, the conveyance and storage of the samples and the preparation of samples for analysis must not be such as to bring about any significant change in the results of the analysis.
Reduction of frequency of sampling, etc.
9 

(1) Where a survey of any waters classified for the purposes of these Regulations shows that the values obtained for any parameters are considerably superior to—
(a) the quality required by Schedule 1, or
(b) the standard adopted by the Department as a result of regulation 5 in relation to the waters,
the Department may reduce the frequency of sampling of the waters in relation to that parameter or standard.
(2) The Department may decide that regular sampling and analysis of waters classified under these Regulations is not needed if—
(a) the requirements of paragraph (1) are satisfied in relation to the waters;
(b) there is no pollution of the waters;
(c) there is no risk of the quality of the waters deteriorating; and
(d) the quality of the waters is superior to the minimum required for waters classified as DW1.
Modification of section 4C of the Water Act (Northern Ireland) 1972
10 
Section 4C of the Water Act (Northern Ireland) shall have effect—
(a) as if it imposed a duty on the Department to exercise the powers conferred on it by that section to classify under these Regulations such waters as are necessary to give effect to Directive 75/440/EEC; and
(b) in relation to the performance of that duty, as if subsections (4), (5) and (7) of that section were omitted.
Systematic plan of action
11 
The Department shall draw up a systematic plan of action including a timetable for the improvement of surface water and especially that falling within category DW3.
Revocation of the Surface Waters (Classification) Regulations (Northern Ireland) 1995
12 
The Surface Waters (Classification) Regulations (Northern Ireland) 1995 are hereby revoked.
Sealed with the Official Seal of the Department of the Environment on 20th December 1996.
R. W. Rogers
Assistant Secretary

SCHEDULE 1
Characteristics of Surface Water intended for the Abstraction of Drinking Water
regulations 3, 4, 5, 7, 8 and 9


No in Annex II to 75/440/EEC Parameters DW1 DW2 DW3
   G I G I G I
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   




SCHEDULE 2
regulation 8 Part I Method of Measuring the Values of Parameters

No. in Annex 1 to 79/869 /EEC Parameters Limit of detection Precision Accuracy Method of measurement Materials recommended for the container
1 pH pH unit — 0.1 0.2 Electrometry, measured in situ at the time of sampling without prior treatment of the sample. 
2 Coloration (after simple filtration) mg/l Pt Scale 5 10% 20% Filtering through a glass fibre membrane. Photometric method using platinum-cobalt scale. 
3 Total suspended solids mg/l SS — 5% 10% Filtering through a 0.45 μm filter membrane, drying at 105°C and weighing. Centrifuging (for at least 5 mins with mean acceleration of 2,800 to 3,200 g), drying at 105°C and weighing. 
4 Temperature °C — 0.5 1 Thermometry. Measured in situ at the time of sampling without prior treatment of the sample. 
5 Conductivity at 20°C μs/cm — 5% 10% Electrometry. 
6 Odour (dilution factor at 25°C) — — — By successive dilutions. Glass.
7 Nitrates mg/l NO3 2 10% 20% Molecular absorption spectrophotometry. 
8 Fluorides mg/l F 0.05 10% 20% Molecular absorption spectrophotometry after distillation if necessary. Ion selective electrodes. 
10 Dissolved iron mg/1 Fe 0.02 10% 20% Atomic absorption spectrophotometry after filtering through a filter membrane (0.45 μm). Molecular absorption spectrophotometry after filtering through a 0.45 μm filter membrane. 
11 Manganese mg/l Mn 0.010.02 10%10% 20%20% Atomic absorption spectrophotometry.Atomic absorption spectrophotometry. Molecular absorption spectrophotometry. 
12 Copper mg/l Cu 0.0050.02 10%10% 20%20% Atomic absorption spectrophotometry. Polarography.Atomic absorption spectrophotometry. Molecular absorption spectrophotometry. Polarography. 
13 Zinc mg/l Zn 0.010.02 10%10% 20%20% Atomic absorption spectrophotometry.Atomic absorption spectrophotometry. Molecular absorption spectrophotometry. 
14 Boron mg/l B 0.1 10% 20% Molecular absorption spectrophotometry. Atomic absorption spectrophotometry. Materials not containing boron in any significant quantities.
19 Arsenic mg/l As 0.0020.01 20%10% 20%20% Atomic absorption spectrophotometry.Atomic absorption spectrophotometry. Molecular absorption spectrophotometry. 
20 Cadmium mg/l Cd 0.00020.001 30% 30% Atomic absorption spectrophotometry. Polarography. 
21 Total chromium mg/l Cr 0.01 20% 30% Atomic absorption spectrophotometry. Molecular absorption spectrophotometry. 
22 Lead mg/1 Pb 0.01 20% 30% Atomic absorption spectrophotometry. Polarography. 
23 Selenium mg/l Se 0.005 10% 10% Atomic absorption spectrophotometry. 
24 Mercury mg/l Hg 0.00010.0002 30% 30% Flameless atomic absorption spectrophotometry (cold vaporisation). 
25 Barium mg/l Ba 0.02 15% 30% Atomic absorption spectrophotometry. 
26 Cyanide mg/l CN 0.01 20% 30% Molecular absorption spectrophotometry. 
27 Sulphates mg/l SO4 10 10% 10% Gravimetric analysis. EDTA compleximetry. Molecular absorption spectrophotometry. 
28 Chlorides mg/l Cl 10 10% 10% Titration (Mohr’s method). Molecular absorption spectrophotometry. 
29 Surfactants (reacting with methylene blue) mg/l (lauryl sulphate 0.05 20%  Molecular absorption spectrophotometry. 
30 Phosphates mg/l P2O5 0.02 10% 20% Molecular absorption spectrophotometry. 
31 Phenols (phenol index) parani-traniline 4 amino-antipyrene mg/l C6H5OH 0.00050.001 0.000530% 0.000550% Molecular absorption spectrophotometry. 4 aminoantipyrine method. Paranitraniline method. Glass.
32 Dissolved or emulsified hydro- carbons (after extraction by petroleum ether) mg/l 0.010.04 20%20% 30%30% Infra-red spectrometry after extraction by carbon tetrachloride. Gravimetry after extraction by petroleum ether. Glass.
33 Polycyclic aromatic hydro-carbons mg/l 0.00004 50% 50% Measurement of fluorescence in the UV after thin layer chromatography. Comparative measurements in relation to a mixture of six control substances with the same concentration. Glass or aluminium.
34 Total pesticides (parathion, hexachloro- cyclohexane, dieldrin) mg/l 0.0001 50% 50% Gas or liquid chromatography after extraction by suitable solvents and purification. Identification of the constituents of the mixture. Quantitative analysis. Glass.
35 Chemical oxygen demand (COD) mg/l O2 15 20% 20% Potassium dichromate method. 
36 Dissolved oxygen saturation rate % O2 5 10% 10% Winkler’s method. Electro-chemical method. Glass.
37 Biochemical oxygen demand (BOD5) (at 20°C without nitrification) mg/l O2 2 1.5 2 Determination of dissolved oxygen before and after five day incubation at 20°C ± 1°C in complete darkness. Addition of a nitrification inhibitor. 
38 Nitrogen, Kjeldahl method (except NO2 or NO3) mg/l N 0.3 0.5 0.5 Mineralisation, distillation by the Kjeldahl method and ammonium determination by means of molecular absorption spectrophotometry or titration. 
39 Ammonium mg/l NH4 0.010.1 0.0310% 0.0320% Molecular absorption spectrophotometry. 
40 Substances extractable with chloroform mg/l ()   Extraction at neutral pH value by purified chloroform, evaporation in vacuo at room temperature, weighing of residue. 
43 Total coliforms /100 ml 5500   Culture at 37°C on an appropriate specific solid medium (such as Tergitol lactose agar, Endo agar, 0.4% Teepol broth) with filtration or without filtration and colony count. Samples must be diluted or, where appropriate, concentrated in such a way as to contain between 10 and 100 colonies. If necessary, identification by gasification.Alternative method:— Method of dilution with fermentation in liquid substrates in at least three tubes in three dilutions. Sub-culturing of the positive tubes on a confirmation medium. Count according to MPN (most probable number). Incubation temperature 37°C ± 1°C. Sterilised glass.
44 Faecal coliforms /100 ml 2200   Culture at 44°C on an appropriate specific solid medium (such as Tergitol lactose agar, Endo agar, 0.4% Teepol broth) with filtration or without filtration and colony count. Samples must be diluted or, where appropriate, concentrated in such a way as to contain between 10 and 100 colonies. If necessary, identification by gasification.Alternative method:— Method of dilution with fermentation in liquid substrates in at least three tubes in three dilutions. Sub-culturing of the positive tubes on a confirmation medium. Count according to MPN (most probable number). Incubation temperature 44°C ± 0.5°C. Sterilised glass.
45 Faecal streptococci /100 ml 2200   Culture at 37°C on an appropriate specific solid medium (such as sodium azide) with filtration or without filtration and colony count. Samples must be diluted or, where appropriate, concentrated in such a way as to contain between 10 and 100 colonies.Alternative method:— Method of dilution in sodium azide broth in at least three tubes in three dilutions. Count according to MPN (most probable number. 
46 Salmonella 1/5,000 ml1/1,000 ml    Concentration by filtration (on membrane or appropriate filter). Inoculation into pre-enrichment medium. Enrichment and transfer into isolating gelese. Identification. Sterilised glass.














 Part II Minimum Annual Frequency of Sampling for each Parameter

Population Served Classification DW1 Classification DW2 Classification DW3
 I II III I II III I II III
<10,000 1 1 1 1 1 1 2 1 1
> 10,000 to ≤30,000 1 1 1 2 1 1 3 1 1
>30,000 to ≤100,000 2 1 1 4 2 1 6 2 1
>100,000 3 2 1 8 4 1 12 4 1


