Furthermore, the World Health Organisation is revising its guidelines for lead in drinking water, the outcome of which might be a significant reduction in the maximum permitted concentration. This is likely to trigger a review of EEC and UK standards.

In some areas, optimal treatment of water may not bring about a reduction in lead concentrations below the current or any possible future maximum permitted concentration at the customer's tap. In these cases, replacement of all lead pipes is likely to be the only practicable solution.

The Department of the Environment commissioned WRc to assess the cost-effectiveness of lead pipe replacement programmes using existing data from the Water Industry. Alternative solutions to the lead problem including water treatment and tap filters were also assessed.

A database was constructed to enable the data assimilated during this project to be input and to permit updates to be made as and when further data become available. This will also allow updates to the conclusions. The report contains results on the occurrence of lead pipes, current lead levels, the effectiveness of alternative solutions and the costs of these solutions and lead pipe replacement programmes for all water quality zones England and Wales. Geographical areas are ranked according to the order of priority for replacement programmes.

An accompanying report (WRc Report No. DoE 2962-/1) contains details of the database and the data and assumptions used to draw the conclusions.

Copies of this report may be available as an Acrobat pdf download under the 'Find Completed Research' heading on the DWI website.