The Drinking Water Quality Regulator for Scotland (DWQR) has said that Scottish Water’s customers continue to receive a supply of very high quality drinking water which they can use with confidence - but is warning over failures in asset maintenance.

The comments come in the twenty first report from the DWQR which provides a summary of the quality of Scotland’s public water supplies for 2022.

The report says that the standard of drinking water quality in 2022 continues to be maintained at similar levels compared to previous years with only 116 of the thousands of samples taken from customers’ taps not meeting regulatory limits.

However, the DWQR has flagged up the detection of bacteria at two of Scottish Water’s service reservoirs which required customers to boil their water as a precaution whilst investigations took place.

Introducing the annual report, Sue Petch, the Drinking Water Quality Regulator for Scotland, said:

“Scottish Water must ensure that drinking water quality continues to be its top priority and that this is safeguarded through diligent operation, maintenance and investment in its water supply systems.”

The report states:

“Our assessment showed significant failings in Scottish Water’s maintenance of these assets. Further investigation into the approach to maintenance and inspection of service reservoirs has shown a backlog of inspection and repair.”

The regulator said it is currently progressing enforcement action to ensure a robust programme of work is implemented “to address this in the fastest possible time.”

DWQR’s site audit programme of work returned to pre-pandemic levels of activity during 2022. Findings included highlighting issues relating to filter performance, ensuring consistent disinfection of the supply and the recording of information in relation to tankering activity. Recommendations for improvement have been given to Scottish Water which the regulator will monitor to ensure completion.

Sue Petch said that the standard of drinking water quality in 2022 continues to be maintained at similar levels compared with previous years with only 116 of the thousands of samples taken from customers taps not meeting regulatory limits.

“This level of compliance is achieved through sustained efforts by Scottish Water to understand the risks posed to drinking water quality and mitigate against them so that there are no impacts on customers. This is done through rigorous treatment of water and extensive monitoring to verify the quality of the supply.”

She added that, in 2022, Scottish Water carried out a total of 297,284 regulatory tests on Scotland’s drinking water with numerical standards and many more for operational reasons such as following a burst main.

“Of the 139,971 tests taken to represent water at consumers taps, 99.92% complied with the standards. In 2022 Scottish Water carried out sufficient water sampling as required by the regulations and the data shows a continued high level of compliance with standards. A further 60,671 tests were carried out on water supplied from treatment works and all but 25 of these tests met the required standards which is similar to the previous year’s performance.”

Her report said Scottish Water also reports the numbers of ‘contacts’ received from consumers about the quality of their drinking water and there were 16,618 such contacts during 2022, which is “a significant improvement on the 23,770 contacts received in 2021.”

Many of the customer contacts were received in 2021 due to an incident in central Scotland, where exceptionally low reservoir levels caused manganese to enter the treatment works, leading to discoloured supplies, the report said.

“It is therefore unsurprising to see a significant reduction in discoloured water complaints in 2022. It is noteworthy that there have also been reductions in the number of complaints relating to the taste and odour of the water supply.”

Scottish Water has welcomed the report by the Drinking Water Quality Regulator.

Welcoming the key findings of the DWQR report, Alex Plant, Scottish Water’s chief executive, said:

“We are pleased that the independent report by DWQR has found that the water we delivered to our customers has continued to be of high quality.

“The regulatory standards set for us are among the most stringent anywhere in the world. Weather extremes, including very cold temperatures followed by a thaw last December and a long dry spell last summer, presented us with some real challenges to keep customers’ supplies flowing and maintaining those high standards.

“Ensuring high quality drinking water is one of the most important things we do. We must continue to respond effectively to areas where the DWQR identifies areas for improvement, invest in the capability and resilience of our network, and ensure that our customers can continue to enjoy the highest level of confidence and trust in their water.”

Click here to download the report in full