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 Essex and Suffolk 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.
Essex and Suffolk Water continues to supply you with drinking water of a high quality. In 1999, 99.89% of more than 102,800 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 Essex and Suffolk 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 Essex and Suffolk Water to further improve its performance.
2. Bacteria
Whenever bacteria are found in water samples Essex and Suffolk Water investigates immediately.
Occasionally low numbers of bacteria were detected in the water leaving a small number of water treatment works and service reservoirs during 1999. The number of bacteriological failures at consumers' taps was 0.5% of the samples taken. Some of these failures may be due to the condition of the tap and not the water itself. The bacteria found were not harmful to consumers' health.
All the contraventions of the microbiological standards were considered trivial or unlikely to recur, except that the Inspectorate considered enforcement action was necessary for improvements to be made at one service reservoir.
3. Lead
Essex and Suffolk Water met the standard for lead in all 994 samples taken. 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. If failures occur the householder would be 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.
4. Iron and Manganese
One sample from 591 taken failed the standard for manganese during 1999. The number of zones contravening the standard for iron has decreased over the last three years. This overall improvement reflects the impact of the programme of work being carried out by Essex and Suffolk Water to renovate its distribution system. The programme is ongoing, with Essex and Suffolk Water being required to renovate more than 1,000km of mains from 1999 to 2010.
These two parameters provide a good indication of the overall condition of the mains used to distribute drinking water through the region.
5. Cryptosporidium
No instances were reported to the Inspectorate of the detection of cryptosporidium in water leaving Essex and Suffolk Water's water treatment works during 1999. 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. Essex and Suffolk Water identified that there was significant risk at four of its sites and it has made arrangements for continuously sampling and monitoring the treated water at each of 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
During 1999, five incidents in which drinking water quality deteriorated were reported to the Inspectorate. The Inspectorate has investigated and reported on each incident.
Three of the incidents involved the supply of discoloured water to consumers. At Stradbrooke in Suffolk, the discolouration arose as a result of burst mains in the distributions system. The second incident arose following the refurbishment of booster pumps serving the Wenhaston area of Suffolk which caused an increase in water velocity and disturbed mains sediment. The third incident, which affected parts of Great Yarmouth, resulted from planned overnight work on the mains system overrunning into the morning peak demand period. The resultant changes in flow pattern caused some disturbance of main sediment. The two remaining incidents involved the detection of low level microbiological contamination. The first, in Stock, Essex, arose following the repair of a burst main. The remaining incident affected Flixton Water Tower and the area that it supplies.
7. Determinations in 1999
Parameter
Total
Contravening PCV No % Coliforms 4478 23 0.5 Faecal coliforms 4478 2 < 0.1 Colour 549 0 0.0 Turbidity 549 0 0.0 Odour 574 1 0.2 Taste 574 1 0.2 Hydrogen ion 549 0 0.0 Nitrate 557 0 0.0 Nitrite 2109 29 1.4 Aluminium 549 0 0.0 Iron 1618 13 0.8 Manganese 591 1 0.2 Lead 994 0 0.0 PAH 264 0 0.0 Trihalomethanes 357 12 3.4 Total pesticides 1168 0 0.0 Dimethoate 100 0 0.0 Isoproturon 1168 0 0.0 Simazine 1168 0 0.0 Other pesticides 51408 0 0.0 Nickel 77 0 0.0 Phosphorus 529 0 0.0 Sulphate 110 0 0.0 All others 8716 0 0.0 Total 83234 82 0.1
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Drinking Water Inspectorate,
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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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