Archive:
(for archive/historical purposes, this document has not been updated)Index of Contents:
- Introduction
- Bacteria
- Pesticides
- Lead
- Iron and Manganese
- Cryptosporidium
- Drinking Water Quality Incidents
- Determinations in 1998
1. Introduction
The Drinking Water Inspectorate (DWI) checks that water companies supply water that is safe to drink when it reaches your home. This leaflet summarises the results of our checks on York Waterworks plc during 1998. and should be read in conjunction with DWI's "How Good is the Drinking Water ?" leaflet which is available from us free of charge.
York Waterworks continues to supply you with drinking water of a high quality. The number of results not meeting the standards has fallen consistently since 1991 and in 1998, 99.63% of more than 7,900 tests met the standards. This is below the overall figure for England and Wales of 99.78%.
None of the failures in 1998 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 1998 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 improve its performance.
2. Bacteria
Whenever 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 1998. The bacteria found were not harmful to consumers’ health and subsequent samples demonstrated that water quality was fully satisfactory. All of the Company’s service reservoirs met the required standard for total coliforms. At one service reservoir low numbers of bacteria were detected were detected on one occasion and the Company took appropriate remedial action.
3. Pesticides
York Waterworks carried out over 2,000 tests for individual pesticides during 1998 and 8 failed to meet the stringent standard. This was a 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. The Inspectorate required York Waterworks to take action to increase the extent of treatment at this works.
4. Lead
York Waterworks continues to have samples occasionally failing the standard for lead, even where additional treatment has been installed to reduce the amount of lead picked up by water from pipework. In all cases the householder has been informed of the problem. 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 from us free of charge.
5. Iron and Manganese and polycyclic aromatic hydrocarbons (PAH)
These three parameters provide a good indication of the overall condition of the mains used to distribute drinking water through the region.
The number of samples failing the standard for iron increased from 1997 and the Inspectorate initiated action which required York Waterworks to undertake remedial work to flush the mains in the affected areas. No samples failed the standard for manganese and a single sample failed the standard for PAH.
6. Cryptosporidium
Cryptosporidium is a tiny micro-organism which can sometimes cause a form of diarrhoea called cryptosporidiosis. No instances were reported to the Inspectorate of the detection of cryptosporidium in water leaving York Waterwork’s water treatment works during 1998.
Water companies will shortly be required to sample continuously and analyse daily for cryptosporidium in the treated water at their most vulnerable sites. It will be an offence if they fail to meet a new treatment standard.
7. Drinking Water Quality Incidents
No incidents were reported by the Company to the Inspectorate in 1998.
8. Determinations in 1998
Parameter
Total
Contravening PCV No % Coliforms 520 1 0.2 Faecal coliforms 520 0 0.0 Colour 169 0 0.0 Turbidity 520 0 0.0 Odour 41 0 0.0 Taste 40 0 0.0 Hydrogen ion 520 0 0.0 Nitrate 52 0 0.0 Nitrite 134 7 5.2 Aluminium 71 0 0.0 Iron 224 7 3.1 Manganese 55 0 0.0 Lead 120 1 0.8 PAH 18 1 5.6 Trihalomethanes 16 0 0.0 Total pesticides 104 0 0.0 Isoproturon 104 8 7.7 Other pesticides 1904 0 0.0 All others 1430 0 0.0 Total 6552 25 0.4
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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
Updated 11 July 2001
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