Archive:
(for archive/historical purposes, this document has 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 Bristol Water plc 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.
Bristol Water continues to supply you with drinking water of a high quality. In 1999, 99.92% of more than 53,400 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 Bristol 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 Bristol Water to further improve its performance.
2. Bacteria
Whenever bacteria are found in water samples Bristol Water investigates immediately. Low numbers of bacteria were detected in 0.2% of samples from consumers taps. The bacteria found were not harmful to consumers' health. The number of bacteriological failures at consumers' taps remains similar to recent years. Many of these failures may be due to the condition of the taps and not the water itself.
3. Lead
Bristol Water had no samples failing the standard for lead in 1999. However, 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. In many cases this is due to the consumer's pipework being made of lead. 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.
Seven samples failed the standard for iron, an improvement on 1998, and one failed the standard for manganese. This is an overall improvement and reflects the programme of work being carried out by Bristol Water to renovate its distribution system. The programme of improvement is ongoing, with Bristol Water being required to renovate more than 254km of mains by 2003.
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 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 determine if there was any significant risk of contamination. Bristol Water identified that there was significant risk at sixteen of its sites and is now continuously sampling and monitoring the treated water at four sites, is providing additional treatment at seven sites and has shut down five sites. 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 events regarded as constituting incidents came to the attention of the Inspectorate in 1999.
7. Determinations in 1999
Parameter
Total
Contravening PCV No % Coliforms 2947 6 0.2 Faecal coliforms 2947 1 < 0.1 Colour 409 0 0.0 Turbidity 419 0 0.0 Odour 414 0 0.0 Taste 409 0 0.0 Hydrogen ion 409 0 0.0 Nitrate 551 0 0.0 Nitrite 552 0 0.0 Aluminium 409 0 0.0 Iron 599 7 1.2 Manganese 425 1 0.2 Lead 210 0 0.0 PAH 287 13 4.5 Trihalomethanes 210 0 0.0 Total pesticides 890 0 0.0 Other pesticides 4464 0 0.0 Ammonium 408 0 0.0 Antimony 105 0 0.0 All others 11199 0 0.0 Total 28263 28 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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