Archive:
(for archive/historical purposes, these documents have not been updated)Index of Contents:
- Introduction
- Bacteria
- Lead
- Iron and Manganese
- Cryptosporidium
- Drinking Water Quality Incidents
- Determinations in 1999
1. Introduction
The Drinking Water Inspectorate (DWI) checks that water companies supply water that is safe to drink when it reaches your home. This document summarises the results of our checks on North Surrey Water Limited during 1999 and should be read in conjunction with DWI's "How Good is the Drinking Water?" leaflet which is available here and also from us free of charge from the address at the end of this document.
North Surrey Water continues to supply you with drinking water of a high quality. In 1999, 99.91% of more than 12,600 tests met the standards. This is above the overall figure for England and Wales of 99.82%.
None of the failures in 1999 were likely to harm consumers' health. We assessed each one and, where necessary, we have required North Surrey Water to take action to prevent further failures.
Although the 1999 results are good, we know that there are some matters of everyday concern to consumers. These are detailed below including the steps taken by North Surrey Water to further improve its performance.
2. Bacteria
Whenever bacteria are found in water samples North Surrey Water investigates immediately. No bacteria were detected in water leaving treatment works. Low numbers of bacteria were detected on seven occasions in water leaving service reservoirs during 1999. The bacteria found were not harmful to consumers' health. Bacteria were detected in one (0.1%) sample from a consumers' tap and which could have been due to the condition of the tap and not the water itself.
3. Lead
No samples failed the lead standard in 1999. The Drinking Water Inspectorate advises consumers living in properties with lead pipes to seek advice from their water company. A DWI leaflet about lead in drinking water is also available here and from us free of charge from the address at the end of this document.
4. Iron and Manganese
These two parameters provide a good indication of the overall condition of the mains used to distribute drinking water through the region.
Two samples failed the standard for iron and none the standard for manganese in 1999. This continuous recent improvement reflects the programme of work being carried out by North Surrey Water to renovate its distribution system. The programme is ongoing, with North Surrey Water being required to renovate more than 180km of mains by 2007.
5. 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 water but due to new regulations water companies are now required by law to sample continuously and analyse daily for Cryptosporidium in the treated water at those sites which have a potential vulnerability. All water companies had to initially conduct risk assessments at their sites to identify if there was any significant risk of contamination. North Surrey identified that there was significant risk at three of its sites and is now continuously sampling and monitoring the treated water at these sites. At all these sites, the Company is required to ensure adequate treatment is in place and it is an offence if the new treatment standard for Cryptosporidium is exceeded. In addition to the regulatory requirement, the Company is able to get early warning of any treatment problems from this monitoring system.
6. Drinking Water Quality Incidents
No incidents were reported to the Inspectorate during 1999.
7. Determinations in 1999
Parameter
Total
Contravening PCV No % Coliforms 1289 1 0.1 Faecal coliforms 1289 0 0.0 Colour 135 0 0.0 Turbidity 134 0 0.0 Odour 137 0 0.0 Taste 137 0 0.0 Hydrogen ion 696 0 0.0 Nitrate 135 0 0.0 Nitrite 135 0 0.0 Aluminium 133 0 0.0 Iron 158 2 1.3 Manganese 135 0 0.0 Lead 56 0 0.0 PAH 57 0 0.0 Trihalomethanes 66 0 0.0 Total pesticides 219 0 0.0 Other pesticides 2362 0 0.0 All others 972 0 0.0 Total 8245 3 < 0.1
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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@detr.gov.uk
Published 12 July 2000 / Updated 11 July 2001
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