Drinking Water Quality in Scotland 2018 - Private Water Supplies

Issued on behalf of Scotland’s Drinking Water Quality Regulator.

In 2018, a total of 42,440 tests were taken from regulated private water supplies which are those supplying more than 50 people or a commercial activity. 93.5 per cent of tests met the required standard, but 11% of these supplies had a sample that contained E.coli, a bug which indicates faecal contamination and potentially causes serious illness. Compliance figures have not changed significantly for the past three years, suggesting that limited improvements are been made, in spite of efforts by local authorities and the existence of a Scottish Government grant.

Private water supplies were also affected by the very dry weather in 2018 and local authorities reported that the owners of some 500 supplies contacted them for emergency assistance when their supplies ran dry.

Private water supplies are those owned and managed by individuals rather than Scottish Water and around 3.6 per cent of the Scottish population receive their water from them. The supplies range from those serving a single house to much larger numbers of houses as well as hotels, tourist accommodation and other businesses. Many of the very small types of supplies have little or no treatment and where water from these supplies does not meet the standards, there may be a risk to the health of those drinking from them.

According to the latest report from Scotland’s Drinking Water Quality Regulator (DWQR), a significant number do not meet the required drinking water standards and need to make  improvements.

Sue Petch, Drinking Water Quality Regulator, said:

“I am concerned with the poor quality of some of the private water supplies in Scotland, particularly those that tested positive for E. coli. It is very important that these supplies are improved so that people using them have a safe and reliable supply of drinking water.

“Advice and information is available from local authorities who also provide a grant which can help towards the costs of improvement.”


A full copy of Drinking Water Quality in Scotland – Private Water Supplies 2018 is available at www.dwqr.scot

  • Private Water Supplies are regulated by local authorities – DWQR has a role to supervise this and provide support and advice.
  • The DWQR is independent of Scottish Ministers and exists to enforce the drinking water quality regulations and ensure that drinking water quality in Scotland is of the highest possible standard. DWQR reviews water quality data from samples taken by Scottish Water and undertakes targeted audits examining all aspects of its operations. An annual report is presented to Scottish Ministers detailing the assessment of drinking water quality during the previous year for both public and private water supplies.
  • It is estimated that around 200,000 people rely on a private water supply for their drinking water, with many thousands more using them occasionally, typically in holiday accommodation. Regulated (formerly known as Type A) private water supplies provide more than 10 cubic metres per day, serve greater than 50 people or a commercial or public activity. Regulated supplies must be risk assessed and sampled by the local authority.  Smaller, exempt (formerly Type B) supplies typically serve one or two private dwellings and are sampled at the request of the owner or user.
  • Some of these supplies have limited or no treatment. The main risk to health comes from microorganisms, including E. coli. The regulations governing the quality of regulated private water supplies are The Water Intended for Human Consumption (Private Supplies)(Scotland) Regulations 2017. These regulations came into force in October 2017.
  • Various treatment options are available for private water supplies. Disinfection often uses ultra-violet light, which can be relatively simple to install and maintain, but may require pre-filtration to remove substances such as iron, manganese and natural colour in the water. All treatment processes require some maintenance and specialist advice may need to be sought.
  • The Scottish Government has introduced a private water supply hub to enable owners and users to access clear and simple information to help them manage their supply.
  • A Scottish Government non-means tested grant of £800 per property is available for improving private water supplies. This may be accessed, along with advice on improving a private water supply, by contacting the environmental health department of the relevant local authority.

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