We have thorough and rigorous processes to test the quality of drinking water we supply to our customers. Every year, we take thousands of samples throughout our supply network to check compliance with the standards set down in national and European legislation.
In 2009, we carried out more than 420,000 tests as part of our monitoring, and achieved 99.98 per cent compliance for samples taken at customer's taps. This gave us the best drinking water quality of all the major water and sewerage companies.
Our water supply system serves more than 8 million people, and unforeseen events occasionally result in some customers receiving water that does not meet our usual high standards. Of the small number of failures that occasionally occur, many are short-lived or caused by customer's fittings. All are immediately investigated.
During 2009, there were six significant drinking water events, all of which were reported to, and investigated by, our regulator the Drinking Water Inspectorate (DWI). We have analysed the causes and, from the lessons learnt, put in place actions to mitigate a recurrence, such as installing an additional process at one of our groundwater treatment works near Reading.
Like the rest of the water industry, we agree a business plan with our economic regulator Ofwat every five years, setting out our major investment proposals, as part of the Price Review process.
We completed ten improvement programmes in the five years to 2010, and have agreed a further 11 in our business plan for the period up to 2015.
These include schemes to reduce nitrate and pesticides. We are trying to find a sustainable means of reducing some pesticides through a liaison programme with local farmers and manufacturers. By influencing the application and types of pesticides used, we are aiming to minimise the risk of run-off into rivers, from which we take water. We will do this in areas around our major west London treatment works, through to smaller sources such as Harpsden, near Henley, and Moreton-in-Marsh, in the Cotswolds.
Other projects involve installing equipment to reduce nitrate levels at groundwater treatment works in Wantage, Oxfordshire, and in Westerham in Kent.
Many older properties in our region have lead pipes connecting the house to the water main in the street, which can increase lead levels in tap water.
The hard water that occurs naturally in our area forms a scale on the inside of the pipes, which helps reduce lead concentrations. In areas where these exceed current or future requirements, we have introduced treatment processes to further reduce lead levels. We plan to install this at a further five treatment works by 2015.
Although this has been very effective, in some areas samples continue to show higher lead levels than those required by new standards that come into effect in 2013. In our investment plans, agreed with Ofwat and the Drinking Water Inspectorate, we are aiming to replace more than 30,000 lead pipes in these areas.
We add no fluoride to any of our supplies. Health authorities in some parts of the UK have made arrangements with the local water company to fluoridate tap water in an effort to reduce tooth decay.
Legislation requires health authorities to consult the local community before new schemes of this sort are introduced. We are aware of no proposals for this in our region.
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