Private water supplies: an agile scope of the literature

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Introduction

Private water supplies are a common source of drinking water in rural parts of the UK. A need to understand risk associated with microbiological and chemical contamination prompted this review. We looked at what is known about health risks, how people feel about these risks, and how climate change might affect water quality. 

The aim was to understand health risks from private water supplies, user views and experiences, and possible effects of climate change on water safety. 

Main points

How up to date is this evidence?

We carried out the searches for this scoping review in May 2023 and identified studies published between 1996 and 2016.

What we found

• No systematic reviews on health risks were identified; 15 primary studies were included.
• Most studies examined water quality and whether supplies met legal standards, rather than measuring direct health effects.
• Many private water supplies did not meet water quality limits. This does not always indicate a health risk, as some limits are set for technical rather than health reasons.
• In studies comparing supply types, private supplies failed standards more often than public supplies.
• Two outbreaks of gastrointestinal illness were reported, though the link to private water supplies was unclear.
• No UK evidence explored public perceptions of water safety. Studies from the USA and Canada showed that most users believed their water was good quality, even when they had concerns about contamination.
• No studies directly examined impact of climate change on private water supplies. However:

• Heavy rainfall was linked to sudden increases in contamination; and
• Some studies found harmful organisms present even when water met standards.

What This Means?

• Evidence suggests that private water supplies may pose health risks, and these risks could increase with climate change.
• Clear guidance, regular testing, and additional checks during high‑risk weather events should be prioritised to protect drinking water quality.
• More UK‑focused research is needed to understand health impacts and users’ views.
• Our search did not capture every possible source, and evidence from other countries may not fully apply to Wales, so findings should be seen as indicative rather than comprehensive.

Technical information

We carried out a scoping review using streamlined yet rigorous systematic review methods to find and summarise evidence. We included studies that examined health risks, people’s views, or climate impacts related to private water supplies. Studies had to be written in English and focus on the UK or Ireland.

For people’s views, we also included relevant research from the USA and Canada to provide wider context, as no UK evidence was available.

Glossary

Private water supply: A drinking water source that does not come from a licensed water supplier i.e., public water company. It includes wells, boreholes, springs, and small shared supplies.

Public water supply: A highly regulated, monitored, and treated (to meet legal standards) water system provided by a licensed water supplier, designed to deliver safe, potable water to buildings (including healthcare premises) for consumption, sanitation, and clinical use.

Private water supply regulations/ standards: Regulations covering the safety and wholesomeness of private water supplies and requiring them to be risk assessed, monitored and where necessary brought up to standard. Although these requirements are different for each country in the UK, they share similarities.

Stakeholders

Health Protection Environmental Team, PHW.