Water Resources

Of the 73 million litres abstracted as untreated water every day, 83% is derived from the River Dee at two major abstraction points, 10% comes from our own upland reservoirs and the remaining 7% from two underground sources.

The River Dee has a long history of association with drinking water supplies, the first abstraction being undertaken in the 1600s to supply water to the City of Chester. Today the River Dee provides essential supplies of water to over two million people living in North East Wales and the North West of England.

Dee Valley works closely with other water abstractors on the River Dee and the Environment Agency to monitor the quality of the water abstracted using highly sophisticated equipment capable of measuring the presence of contamination down to levels of points per thousand million.

The Company's draft Water Resources Management Plan is currently being reviewed by the Welsh Assembly Government. Once direction has been received to publish, a copy will be available to download from this website.

Droughts

Dee Valley has a proven record of water supply during droughts. We have not imposed restrictions on the use of water since 1990. This record has been achieved by the efficient operation of our water resources leading up to and during droughts, aided by our long history of low leakage levels of water from our network of water pipes.

Leakage

Dee Valley has one of the lowest levels of leakage in the water industry in England and Wales.

In 2004/05 the total leakage was 10.63 Ml/d, the majority of which was from the Company’s network of 1,976 kilometres of water mains and 90,000 connecting pipes, some of which are over 100 years old.

The remainder of the leakage is from customer-owned pipes – that part of the supply pipe normally within the curtelage of the customer’s property.

Leakage occurs from bursts or leaks on pipes and from seepage from joints. It is our policy to detect and repair these leaks, many of which remain hidden below ground, as quickly as possible.

Leakage is substantially affected by weather conditions which can cause the ground around the pipes to move often causing cracking of the pipes.

Customers can assist themselves and ourselves by ensuring that leaks are reported as soon as they become evident (Leakline Freephone 0800 298 7112), and by taking simple precautions to prevent bursts caused by frost.

Continuity of Supply

Our aim is to maintain an adequate and safe supply of water to all our customers for 24 hours of every day, 365 days a year.

Occasionally, supplies will be interrupted in order to undertake planned maintenance. At these times we will inform customers in writing in advance of the work, giving them details of the time and dates when their supplies will be affected.

Unplanned maintenance events – normally water mains bursts – cannot be predicted and we have to react to such events. It is our aim to restore supplies as quickly and safely as possible.

During the year ending 31 March 2005, 8,478 properties were affected by unplanned incidents. The following table shows those properties worst affected:

If supplies are affected for more than 12 hours in the case of a burst main, customers may be entitled to compensation unless exceptions apply (see Guaranteed Standards Scheme).

Water Pressure

The national standard for water pressure assumes that a flow of water of 9 litres per minute can be taken from the first cold water tap at premises, whilst maintaining a pressure at the boundary of 10 metres head. This standard is considered adequate for all normal domestic properties.

During the year ended 31 March 2005, 99.9% of all properties supplied were compliant with this standard.

From time to time the pressure in our pipelines can fluctuate. This fluctuation normally results from unusual events such as a burst on a water main or during periods of abnormally high consumption.

We have to be careful to strike the right balance with pressure, as too high a pressure in the water mains can result in higher levels of leakage.

Water Quality

In 2004 Dee Valley Water undertook 14,643 regulatory (National and Directive) analyses. Of these 99.97% complied with current water quality regulations. This high level of compliance stems from our commitment to ensuring that water is fit to drink not only when it leaves the treatment works, but also at the point of supply at customers’ taps.

During 2004 we did not report any incidents to the water quality regulator, the Drinking Water Inspectorate.

Occasionally, our customers report that their supply is discoloured. This is normally caused by sudden water flow changes in the water pipes which can disturb corrosion products present on the inside of the pipes. When informed of these events we take action to flush out and clean the pipes.

Some customers report that they have detected a taste or odour on their water supply. These normally result from our requirement to add chlorine to the water as a disinfectant. This process ensures that water supplies remain bacteriologically safe from the time when they leave our treatment works until they arrive at customers’ taps.