Archive:
(for archive/historical purposes, these documents have not been updated)Index of Contents:
- Introduction
- Bacteria
- Pesticides
- 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 The York Waterworks 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.
York Waterworks continues to supply you with drinking water of a high quality. In 1999, 99.55% of more than 7,800 tests met the standards. This is below 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 York Waterworks 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 York Waterworks to further improve its performance.
2. Bacteria
On the few occasions when bacteria are found in water samples York Waterworks investigates immediately. On a single occasion low numbers of bacteria were detected in the water leaving the Company's water treatment works during 1999. The bacteria found were not harmful to consumers' health and subsequent samples demonstrated that water quality was fully satisfactory. Bacteria were not found in water leaving any of the Company's service reservoirs. There was a single detection of bacteria in a sample taken at the consumer's tap.
3. Pesticides
York Waterworks carried out over 1,900 tests for individual pesticides during 1999 and eight failed to meet the stringent standard. This was the result of higher than usual levels of pesticides in the water abstracted from the River Ouse, which were not completely removed by treatment at the Company's Acomb Landing water treatment works. At the very low concentration found the pesticide detected did not represent any risk to health. A scheme is currently being implemented to ensure that the standard will be met at all times.
4. Lead
Samples 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 water pipes being made of lead. In all cases the householder has been informed of things they can do to reduce lead levels at their tap. 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.
5. 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. There were no failures of the standard for iron or manganese during 1999.
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 water but due to new regulations water companies are required by law to sample treated water continuously and analyse daily for Cryptosporidium at those sites which have a potential vulnerability. All water companies had to initially conduct risk assessments of their water treatment works and associated raw water sources, to identify if there was any significant risk of contamination. York Waterworks identified that there was significant risk at its Acomb Landing site and is now continuously sampling and monitoring the treated water. At this site, 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 problems from this monitoring system.
7. Drinking Water Quality Incidents
During 1999, one incident in which drinking water quality deteriorated was reported to the Inspectorate.
In September, bacteria were detected in the water supply within the water supply to a small number of consumers within a retail park near York, following the final connection of a new main. Although there was no demonstration of a risk to health advice to boil water was issued to the few consumers who were affected whilst action was taken to restore normal water quality. There were no other water quality incidents.
8. Determinations in 1999
Parameter
Total
Contravening PCV No % Coliforms 517 1 0.2 Faecal coliforms 517 0 0.0 Colour 166 0 0.0 Turbidity 517 1 0.2 Odour 40 0 0.0 Taste 40 0 0.0 Hydrogen ion 517 0 0.0 Nitrate 53 0 0.0 Nitrite 143 22 15.4 Aluminium 53 0 0.0 Iron 217 0 0.0 Manganese 52 0 0.0 Lead 118 2 1.7 PAH 39 0 0.0 Trihalomethanes 16 0 0.0 Total pesticides 104 0 0.0 Isoproturon 104 4 3.8 Mecoprop 104 4 3.8 Other pesticides 1728 0 0.0 All others 1426 0 0.0 Total 6471 34 0.5
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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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