Drinking Water Quality in Scotland 2019 - Private Water Supplies

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

In 2019, a total of 48,384 tests were taken from regulated private water supplies, which are those supplying more than 50 people or a commercial activity.

89.8 per cent of tests met the required standard, but 14.5% of these supplies had a sample that contained E.coli, which indicates faecal contamination and potentially causes serious illness. Compliance figures have not improved in recent years, and the 2019 results actually represent a deterioration on 2018 for many types of test. In 2018, 11% of samples contained E.coli.

Private water supplies are those owned and managed by individuals rather than Scottish Water and around 3.3 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 almost certainly represent a risk to health.

Drinking Water Quality Regulator Sue Petch said:

“It is concerning that the quality of private water supplies is not improving and I am especially worried about those supplies that tested positive for E. coli. These supplies represent a risk to the residents, visitors and customers who consume them.

"It is vital that these supplies are improved so that people using them have a safe and reliable supply of drinking water. Local authorities can offer advice and support as well as enabling access to a Scottish Government grant to make improvements.”


A full copy of Drinking Water Quality in Scotland – Private Water Supplies 2019 is available on the Drinking Water Quality Regulator website

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 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 supplies typically serve one or two private dwellings and are only 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.

Press enquiries are handled in the first instance by the Communications Economy desk of the Scottish Government: 0131 244 2614.


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