If your home is not on mains water, you have a private water supply. In the UK these are legal and common, but the responsibility for keeping the water safe sits with you, the owner or user, and local authorities have duties to check many of them.
What counts as a private supply?
A private supply is any drinking water not provided by a water company: a borehole, well, spring, stream, or in some cases collected rainwater. Different rules apply in England, Wales, Scotland and Northern Ireland. In England, the Private Water Supplies (England) Regulations 2016 apply.
Who is responsible?
- It is the owner or occupier’s responsibility to make sure the water is wholesome.
- Local authorities are the regulator for private supplies and must risk-assess and sample supplies in their area.
- Larger and commercial supplies are sampled more often; small supplies are sampled at least every five years.
- For a single dwelling occupied by its owner, the council is not required to monitor the supply but should do so if you ask.
What should you test for?
The main concern is microbiological contamination (such as E. coli and coliform bacteria), followed by chemical and physical checks such as nitrate, metals, pH, turbidity and hardness. What is important for your source depends on the land around it: livestock, septic tanks, farming and geology all matter.
Treatment options
- Sediment filtration: removes particles and helps other treatments work.
- Carbon filtration: improves taste and removes some chemicals.
- UV disinfection: inactivates many microorganisms if the water is clear enough.
- Other systems: reverse osmosis or specific treatments for particular problems.
A treatment system is only as good as its maintenance: filter changes, UV lamp replacement, regular testing and a plan for when it fails. Treatment should be matched to test results, not bought first.
Rainwater for drinking
Rainwater can be used with proper filtration, disinfection and testing, but it is a demanding route. See rainwater harvesting in the UK.
Buying a property or land with a private supply
Ask for recent test results, the location of the source, who owns the source and pipework, and whether you have legal rights to it. Include this in your checks, as described in our guide to finding land and the Land & Planning Due-Diligence Pack.
FAQ
Is well water safe to drink? Not necessarily; test it and treat it based on the results.
Who tests my private water? Your local authority has duties for many supplies; you can also use an accredited laboratory.
Can I drink from a stream? Untreated surface water is high risk and should not be assumed safe.
Sources
- Drinking Water Inspectorate: roles and responsibilities
- The Private Water Supplies (England) Regulations 2016
Educational information, not health or legal advice. Water safety is a serious matter: test your supply and consult your local authority’s environmental health team and a qualified professional. Last checked: September 2026.
