Report No DWI0211

Dec 1994

The Water Quality Centre was invited to undertake a review of water quality within domestic cold water systems. The purpose of the investigation was to highlight any potential for deterioration of water quality within the cold water supply, storage and cold water distribution associated with the systems .

The project was undertaken in line with specifications laid down in the Department of Environment correspondence "Department of the Environment Research Contract EPG\1\9\11, managed by the Drinking Water Inspectorate", dated 7th June 1994.

A total of 125 samples were taken from 25 domestic water systems located in domestic flats, houses and offices.

No Legionellae, coliforms, Escherichia coli, Aeromonas bacteria or Pseudomonas aeruginosa were detected in any of the samples analysed.

No significant increases in bacterial numbers was measured by bacterial colony counts at 22ºC and 37ºC) were detected from any of the 25 systems examined.

One of the aims of the project was to establish if varying cold water storage conditions would have any effect on the quality of stored water. No significant differences in bacterial quality of stored water was observed amongst the different types of storage cisterns examined. However, slightly elevated bacterial colony counts were detected from the uncovered cold water storage cisterns.

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