Buying property with a private water supply

Private water supplies always present problems in a purchase. Whether you are buying a house or part of an estate with a private supply, there is much to consider.

Local authorities and private supplies

In England, private supplies are governed by the Private Water Supplies (England) Regulations 2016, which were amended in 2018 (Regulations). There are subtly different regulations in Wales. They set out the duties of local authorities in relation to the wholesomeness and sufficiency of private supplies and afford them powers to enforce against “relevant persons”. A relevant person is widely defined and will catch the owner or occupier of premises served by the supply, the owner or occupier of land on which any part of the supply is situated, and any person who manages or controls that supply.

Under the Regulations, local authorities are required to register all private supplies and carry out risk assessments. For small private supplies (those supplying under 10 cubic metres of water per day, or roughly fewer than 50 people) assessments must be reviewed at least every five years. Where a supply is suspected to be unwholesome the local authority must investigate, inform those affected and offer advice. If there is a danger to human health, it must serve a “regulation 18 notice” specifying what action needs to be taken to restore wholesomeness. Where a private supply is failing to provide a sufficient supply of water for domestic purposes, the local authority can serve a “section 80 notice”, setting out what steps must be taken to remedy the problem.

Buying a house on a private supply

As the private supply of water is so regulated, it is essential when buying a house to understand where its water comes from. Due diligence must establish the facts. What and where is the source? How does the water reach the house, where is it stored and how is it treated before consumption? Who is the manager of the supply? What is the history of wholesomeness, sufficiency, test results and remedial works? The sales particulars may state “Mains Water” but even this must be questioned. Water direct from the mains is one thing, but where a water company supplies the water from the mains and it is then distributed by a private network of pipes, that is a private distribution network and a “regulation 8” supply subject to the five yearly risk assessments by the local authority.

Most private supplies involve water from a privately owned spring or borehole that serves a single dwelling. Where such a supply has been used solely for domestic purposes (drinking, washing, cooking) and not for any commercial purposes (B&B, holiday cottage or letting to tenants) then the house may escape the requirement for mandatory risk assessment and monitoring by the local authority under the “single dwelling exemption”. The lack of formal oversight may, however, mean that there is no history of water quality testing, and the quality of the water will be an unknown to a buyer. A buyer may request a local authority to carry out a risk assessment, but in this case will need to pay the authority’s costs.

A buyer (and its mortgagee) will also be concerned to understand the legal underpinning of the supply. Where the water is piped from third party land there must be an easement for the continuing right to a supply of water, which should also deal with rights of entry for repair and replacement (in case of landowner default). There may also be separate contractual arrangements with the adjoining landowner covering responsibility for management and maintenance of the supply and payment for water consumption.

Private supplies to houses present real difficulties for a house owner and professional advice may be appropriate to consider the effectiveness of treatment systems. Whether the supply is adequate for modern essentials such as dishwashers and power showers – and even modern boilers – is another question.

Buying an estate with a private supply

The difficulties are greater for the buyer of a farm or part of an estate that has a private supply. Here the buyer will become not just a consumer, but also a manager (a relevant person for the Regulations), which brings much greater responsibility, cost and risk.

Again, due diligence must establish the physical facts of source, pipe routes, pumps and reservoirs. Having a plan of the network from the outset of a transaction is essential – and if the current owners profess vague knowledge of the facts, a buyer must still insist on a plan. As with a single house, the history of test results and treatment systems must be understood, but the issues go deeper.

In addition to the Regulations concerning private supplies, an abstraction licence may also be required for abstraction in excess of 20 cubic metres per day. A buyer must check the licence is assignable and that there have been no breaches of conditions.

A private supply serving several dwellings comes with a heavy maintenance burden, and there is often “someone in the village” who does the daily checks and general management. This knowledge of where everything is and how it works can be a valuable resource for a buyer into the future, but thought needs to be given to the legal status of this person. Often, nothing is written down: is this person a contractor or an employee? Will that employment transfer to the buyer on the purchase? Who is responsible for the actions of this person in the event of negligent management of the water supply? And finally, what happens to that knowledge if that person leaves, or dies?

For obvious reasons, the purchase of part of an estate where a private water supply is being split (whether permanently or in phased completions) throws up further drafting challenges. The sale documentation will need to set out who has management control of which parts of the private supply and for how long; it will contain reciprocal obligations and indemnities, as well as the necessary cross-rights needed by either party for the future. The thinking around these issues is greatly facilitated by having clear plans of the network early in the transaction.

The future 

One quirk of the Regulations at present is that although there are duties on local authorities to act when they become aware of private supplies, there is no corresponding duty on relevant persons to notify authorities that those supplies exist. However, this is likely to change: a 2024 report on the impact and future of the regulatory model and legislative framework surrounding private supplies recommended mandatory registration, ending the single dwelling exemption and requiring additional disclosures regarding private water supplies in the conveyancing process, as well as in the planning process.

Over time the regulation of private supplies and the administrative burden on landowners will only become more onerous. In practice, the capital expenditure for remedial and improvement works and the running costs of managing a private supply will never be covered by the contributions of consumers. Even if users are under contractual obligations to pay for their water, local authorities will intervene and serve section 80 notices if there is any threat to cut users off for non-payment, which makes enforcement of payment problematic.

The obvious duties of care that managers of private supplies owe to the users mean questions of personal liability must be taken seriously. Whilst corporate vehicles can be considered as means to shelter individual landowners from potential liability, their use is not straightforward. Buyers must therefore be warned – owning a private water supply is not for the faint-hearted.

This article is part of the Rural Estates Newsletter 2025, click here to read.

This publication is a general summary of the law. It should not replace legal advice tailored to your specific circumstances.

© Farrer & Co LLP, February 2025