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
- Formal Caution
- 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 Northumbrian 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.
Northumbrian Water continues to supply you with drinking water of a high quality. In 1999, 99.87% of more than 200,400 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 Northumbrian 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 Northumbrian Water to further improve its performance.
2. Bacteria
Whenever bacteria are found in water samples Northumbrian 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 0.3% 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 two treatment works.
3. 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.
4. Iron and Manganese
The number of zones contravening the standards for iron and manganese was similar to that over the last three years. Northumbrian Water is carrying out a programme of work to renovate its distribution system. The programme is ongoing, with Northumbrian Water being required to renovate more than 4,683km of mains from 1999 to 2010.
These parameters provide a good indication of the overall condition of the mains used to distribute drinking water through the region.
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. Northumbrian Water identified that there was significant risk at 26 of its sites and it has made or is making 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, 12 incidents in which drinking water quality deteriorated were reported to the Inspectorate.
Eight of the incidents involved the supply of discoloured water to consumers. In three cases, at Ellington and Lynemouth, Wallsend and Darras Hall, the discolouration arose as a result of burst mains in the distribution system, or following measures to maintain supplies following a burst main. In three other cases, at Ashington, Whitley Bay and areas supplied from Scaling treatment works, discolouration occurred following work carried out by the Company on the distribution system. The remaining two incidents concerned problems with the treatment process at Lartington treatment works, and high demand in the Teeside area.
Three incidents involved loss of disinfection, at Murton treatment works (twice) and New Winning treatment works. The remaining incident related to low level microbiological contamination following the repair of a burst main at Blyth.
7. Formal Caution
In January 2000 the Company received a formal caution, which will remain on the files, having admitted supplying water unfit for human consumption contrary to Section 70 of the Water Industry Act 1991. The incident involved the supply of discoloured water to parts of North Tyneside on 11 May 1998 and occurred during an operation to remove one trunk main from supply and reintroduce an alternative trunk main. The Inspectorate considered that there was sufficient evidence to proceed with a prosecution. However, the evidence suggested that the Company took rapid and effective action to address the problem and amended its working procedures following the incident to minimise the risk of a recurrence. A formal caution was therefore considered to be the most appropriate course of action rather than to proceed with the case before the Magistrate's Court.
8. Determinations in 1999
Parameter
Total
Contravening PCV No % Coliforms 7337 25 0.3 Faecal coliforms 7337 0 0.0 Colour 7337 2 < 0.1 Turbidity 7337 5 0.1 Odour 941 2 0.2 Taste 940 1 0.1 Hydrogen ion 7337 0 0.0 Nitrate 987 0 0.0 Nitrite 987 0 0.0 Aluminium 3469 2 0.1 Iron 3469 69 2.0 Manganese 3469 16 0.5 Lead 1705 14 0.8 PAH 561 0 0.0 Trihalomethanes 550 4 0.7 Total pesticides 1483 1 0.1 2,4-D 1495 1 0.1 Chlorotoluron 1479 1 0.1 Diuron 1479 0 0.0 Isoproturon 1479 22 1.5 MCPA 1495 22 1.5 Simazine 1451 0 0.0 Other pesticides 74491 0 0.0 All others 21659 0 0.0 Total 160274 187 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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