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2. Executive Summary
This is the sixth annual report prepared by the Drinking Water Quality Regulator for Scotland ( DWQR) and submitted to Scottish Ministers. It presents and reviews the information provided by Scottish Water under the Water Supply (Water Quality) (Scotland) Regulations 2001 (the Regulations) and reflects the dealings that the DWQR had with Scottish Water between 1 January and 31 December 2007. The report also presents and reviews information on private supplies provided by the Local Authorities. Section 3 of this report covers drinking water quality at a national level, examining the water quality in sources, at water treatment works, and through the distribution system to consumers' taps. Section 4 breaks the national picture down into the five regions of Scotland represented by the Waterwatch Scotland panel areas, and provides details of water quality at consumers' taps by local authority area.
The drinking water quality results reported by Scottish Water for 2007 show that 363,451 tests were carried out on samples taken from water treatment works, service reservoirs and consumer taps. Of the 160,601 tests on samples taken from consumer taps, 99.76% complied with requirements for which there is a numerical standard, an improvement on 2006. A total of 393 tests gave results which did not meet the standard set out in the Water Supply (Water Quality)(Scotland) Regulations 2001. As in previous years, the largest number of failing samples was for the total coliform and trihalomethane parameters.
Compliance with the key microbiological parameters continued to improve in 2007. There were 78 failures of the coliform bacteria standard at consumers' taps and 5 samples contained E.coli, comparing favourably with 114 and 9 respectively in 2006. Data going back to 2002, when Scottish Water was formed, are shown in Figure 2.1. These clearly show the improvement in microbiology results.
Figure 2.1 Summary of Microbiological Tests on Tap Samples Since 2002
Extensive sampling of raw and final waters for Cryptosporidium was undertaken in 2007 in accordance with the Cryptosporidium (Scottish Water) Directions 2003. Final Water samples were taken from 300 water treatment works, providing 11,393 samples throughout the year. Of these samples, 927 (8.1%) contained Cryptosporidium oocysts, a slight increase on 2006.
DWQR receives details from Scottish Water of events which could affect drinking water quality. In 2007, 64 out of 1,407 water quality events notified to DWQR were classified as incidents and investigated. The exceptionally wet Summer resulted in a number of boil water notices being imposed following detection of Cryptosporidium oocysts at locations where the treatment process was not adequate to deal with the deterioration in source water quality.
In 2007, Scottish Water was contacted 26,702 times by consumers concerned about drinking water quality issues. This represented a reduction of 16% on 2006. The largest category of contacts (37.4%) concerned discoloured supplies.
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