The 2023 Annual Reports for Private Water Supplies has been published by Scotland’s Drinking Water Quality Regulator.
In 2023, the data provided to the DWQR by local authorities showed that there are 23,034 private supplies in Scotland, with an increase of 205 from 22,829 supplies reported during 2022. This data shows that around 3.5% of the Scottish population rely on a private water supply. However this figure is an underestimate of the population served, as it does not include the large number of visitors to commercial premises including tourists; employees; and consumers of products supplied by food premises.
The majority of PWS are located in rural areas, though some are located in areas where there is a public supply of water available. Highland Council has the most Regulated supplies, and Aberdeenshire has by far the largest number of PWS overall.
The information provided by local authorities for this report shows that compliance by both local authorities and PWS owners and users must get better. This will involve a greater emphasis by owners and users of PWS to maintain and improve their supplies; and for local authorities to prioritise PWS sampling and risk assessment to protect public health.
Recent legislation to licence short term let properties in Scotland has led to a rise in Regulated supplies across the country, and local authorities are progressing in processing this increase in supplies based on public health need. The increase in PWS reported in 2023 is partly due to the registration of these properties. This makes year-on-year comparisons difficult as the amount of supplies does not remain static.
Compliance with the requirement to sample all Regulated supplies annually has decreased across Scotland from 66% in 2022 to 65% in 2023. A notable drop in performance was observed in the Argyll and Bute Council area, where compliance dropped from 96% to 59% (although their Regulated supplies have increased from 522 to 764). Compliance from Perth and Kinross Council also fell from 72% in 2022 to 55%. Highland and Dumfries and Galloway Councils have both slightly increased their compliance, and Scottish Borders and Aberdeenshire Councils have been consistent with good compliance.
In 2023 the parameter with most failures was coliform bacteria, with 21.2% of samples failing this test. Coliform bacteria are present in soil and the environment, so these failures show the lack of effective treatment on many private water supplies. This demonstrates why it is important for local authorities to continue to risk assess and test supplies, and for owners and users to maintain their treatment.
