Index of Contents:
- Introduction
- Coliform Bacteria
- Pesticides
- Lead
- Iron and Manganese
- Cryptosporidium
- Drinking Water Quality Incidents
- Further Information
1. Introduction
The Drinking Water Inspectorate (DWI) checks on behalf of the Government that water companies supply water that is safe to drink. This leaflet summarises the results of our checks on South West Water Limited during 2001. You should read it alongside DWI’s leaflet, How Good is the Drinking Water? which gives more details on the standards and tests. This is available free of charge and on the DWI web site at www.dwi.gov.uk..
South West Water continues to supply you with drinking water of a high quality. In 2001, 99.88% of more than 169,000 tests met the drinking water standards. This is close to the overall figure for England and Wales of 99.86%. The tests are carried out on samples taken from water treatment works, service reservoirs and consumers’ taps.
None of the failures of the standards in 2001 were considered harmful to consumers’ health. Each failure was assessed and, where necessary, South West Water has taken action to prevent further failures.
Although the 2001 results are good, there are some matters which may concern you. These are detailed below, including any steps taken by South West Water to further improve its performance.
2. Coliform bacteria
Occasionally, coliform bacteria may be found in drinking water samples; these are not usually considered harmful to consumers’ health. If coliform bacteria are detected, South West Water investigates immediately.
During 2001, low numbers of coliform bacteria were detected in the water leaving a small number of water treatment works and service reservoirs. The standard at service reservoirs permits 5% of samples to contain coliform bacteria and, in 2001, none of the Company’s service reservoirs failed the standard.
Coliform bacteria were detected in less than 1% of the water samples taken from consumers’ taps. Many of these failures could be due to the condition of the tap and not the water itself. The standard permits 5% of samples in a water supply zone to contain coliform bacteria. All zones met the standard.
3. Pesticides
South West Water carried out more than 61,300 tests for individual pesticides during 2001 and all but 11 samples met the stringent standard. This reflects the significant investment in recent years to remove pesticides from drinking water. At the very low concentrations found, the pesticides detected did not represent any risk to health.
4. Lead
Samples do occasionally fail the standard for lead, even where additional treatment has been installed to reduce the amount of lead picked up by water from pipework. These failures are usually due to the consumers’ water pipes being made of lead. Whenever a failure occurs, the householder is informed of any problems by South West Water and advised of things they can do to reduce lead levels in the water at their kitchen tap.
If you are concerned about the possibility of lead in your drinking water, you should contact South West Water to see whether there is a problem. A leaflet about lead in drinking water is available from DWI free of charge and can also be found on the DWI web site.
Two of 492 samples taken by South West Water failed the standard for lead during 2001.
5. Iron and manganese
These two parameters provide a good indication of the overall condition of the mains used to distribute drinking water throughout the area of supply.
During 2001, only 59 of 2,759 samples taken for iron failed the standard. Only ten of 2,759 samples taken for manganese failed the standard. This reflects the impact of the renovation programme being carried out by South West Water to its distribution system.
Although parts of the programme were significantly affected by the impact of the Foot and Mouth Disease Outbreak, South West Water renovated a total of 384 km of mains during 2000 and 2001. This programme covers most of the areas affected by the failures, and is ongoing with South West Water being required to renovate a further 5,565 km of mains by 2010.
6. Cryptosporidium
Cryptosporidium is a tiny micro-organism that can sometimes cause a form of diarrhoea called cryptosporidiosis. There are a number of sources of Cryptosporidium other than drinking water, New regulations require water companies to sample continuously and analyse daily for Cryptosporidium in the treated water at potentially vulnerable sites.
It is a criminal offence to exceed the new treatment standard for Cryptosporidium.
During 2001, South West Water fulfilled its requirements to carry out continuous sampling and monitoring at 13 of its sites that were identified as being at significant risk from Cryptosporidium. The Company is required to tell the DWI of any failures to meet the treatment standard. South West Water reported no failures during 2001.
In addition, as part of the new regulations, the Company is committed to programmes of work to reduce any potential risk from Cryptosporidium at 29 sites. Two of these programmes were completed during 2001.
7. Drinking Water Quality Incidents
DWI regarded four of the events notified during 2001 by the Company as incidents. The details are shown in the table below.
Three of the incidents, assessed by DWI, were of short duration and South West Water took remedial action. Two recommendations were made regarding sampling and procedures. One incident remains under consideration.
Also In 2001, DWI assessed one incident that occurred in 2000.
Summary of water quality incidents reported in 2001
Type of incident
No.of incidents
Assessment completed
Areas affected
Advice to boil water/not to use water following contamination of supplies
3
Yes
RMB Chivenor (January); Exmouth (June); Muddiford (May7)
Supply of water with taste and odour
1
No
Camelford (October)
8. Further information
If you would like more information about drinking water quality the following leaflets are available free of charge from DWI and can also be found on the DWI web site:
What do we do?
How good is the drinking water?
Problems with your drinking water
Chlorine, smell and taste
Discoloured water
Lead in drinking water
Private water supplies
Water hardness
Tap water, where does it come from and how is it made safe to drink?
Using lead-free solder for drinking water fittings
DWI reports on each water company
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Drinking Water Inspectorate,
Floor 2/A1, Ashdown House, 123 Victoria Street, London, SW1E 6DE
Telephone : 020 7944 5956 - Facsimile : 020 7944 5969
E-mail: dwi.enquiries@defra.gsi.gov.uk
Published 10 July 2002
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