Manual on Treatment for Small Water Supply Systems
DETR/DWI/4936/1
March 2001

This manual is intended to assist local authorities in the UK in discharging their responsibilities for private water supplies. It may also be of use to anyone, in any country, who may be responsible for, or called on to give advice upon, assessment and treatment of small public or private water supplies in the context of their own national regulations.

Some 50 000 private water supplies serve approximately one percent of the population of England and Wales. In Scotland there are about 20 000 private supplies and there are also significant numbers in Northern Ireland. Wholesomeness standards are prescribed in the 1998 EC drinking water Directive. In the UK, regulations incorporate those wholesomeness standards and specify the duties of local authorities in respect of sampling and analysis of private supplies.

Those with responsibilities for assessing, monitoring or improving small water supply systems need to have access to technical advice on a range of issues. These issues include selection and protection of water sources as well as the specification of treatment necessary to improve the quality of water supplies.

This manual provides advice on source selection and protection and on the properties and likely sources of contamination of water. Methodology for assessing the risk of pollution of water sources is provided. The application of water treatment processes is described and small-scale devices that may find application in the treatment of private supplies are reviewed. Test protocols for assessing small scale treatment devices are summarised - these provide a comparable basis against which manufacturers' claims may be assessed and set out test procedures for establishing whether a device might cause any deterioration in the microbiological quality of water during treatment.

The manual includes the addresses of key organisations, provides a list of relevant reference documents, a glossary of technical terms and checklists for risk assessments of small water supplies.

Copies of this report are available from WRc.