---
title: "Private water supplies and Legionella: rules in England, Wales, Scotland and Northern Ireland"
source_url: https://legionella.io/articles/private-water-supplies-legionella-rules-england-wales-scotland-northern-ireland/
canonical_url: https://legionella.io/articles/private-water-supplies-legionella-rules-england-wales-scotland-northern-ireland/
pillar: "UK Legionella Law & Compliance"
summary: "Boreholes, wells and springs sit under different private-water regimes across the UK. How those rules interact with Legionella control."
primary_keyword: "private water supply Legionella UK"
date_published: 2026-07-07
date_reviewed: 2026-07-07
author: "Legionella.io editorial team (REMOTE TECH LTD)"
reviewed_against: "HSE L8 and HSG274 guidance"
region: "United Kingdom"
license: "CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Quote, adapt or republish with attribution to REMOTE TECH LTD and a link to source_url."
license_url: https://creativecommons.org/licenses/by/4.0/
---

# Private water supplies and Legionella: rules in England, Wales, Scotland and Northern Ireland

A borehole, well or spring creates two compliance questions. Is the water safe to drink? And is the building water system safe from Legionella growth and aerosol exposure? Those questions overlap physically, but they are not the same duty.

Private-water rules regulate the source-to-tap drinking-water supply. Legionella control regulates what happens inside tanks, cylinders, pipework, outlets and showers. A private supply can pass drinking-water sampling while the downstream hot-water system still creates Legionella risk.

## The four-nation private-water map

| Nation | Private-water regime to check | Practical Legionella consequence |
|---|---|---|
| England | Private Water Supplies (England) Regulations 2016, through local authorities and DWI reporting [1] | Keep local-authority risk assessment/sampling evidence beside, not instead of, the Legionella risk assessment. |
| Wales | Private Water Supplies (Wales) Regulations 2017; DWI reports separately on Wales [2][3] | Welsh private supplies in rented, commercial or public use settings need the Wales-specific file. |
| Scotland | Local council registration, testing and risk-assessment route, with DWQR oversight and guidance [4] | A Scottish borehole or spring site should cite Scottish private-water guidance, not DWI England rules. |
| Northern Ireland | Private Water Supplies Regulations (Northern Ireland) 2017 via DAERA / DWI NI [5] | NI sites need the DAERA/DWI NI private-water file plus a separate HSENI/L8 Legionella file. |

The country column matters because "PWS 2016" is not UK-wide shorthand. If the site is in Wales, Scotland or Northern Ireland, the private-water legal source changes.

## Why drinking-water sampling is not Legionella control

Private-water assessment asks whether the supply could be unwholesome or a danger to human health as drinking water. It looks from source to tap, including abstraction, storage, treatment and distribution. That is essential, but it does not answer the Legionella question by itself.

Legionella risk is driven by amplification and exposure. Water may arrive from a spring with low numbers of environmental organisms, then sit in a warm tank, stagnate in a dead leg, collect biofilm in a shower hose and become inhaled as droplets. That is a building water-system problem, controlled under the HSE or HSENI Legionella framework [6][7].

The simplest audit test is this: if your file has a council water result but no outlet list, no schematic, no hot/cold control record and no flushing regime, you have a private-water file, not a Legionella file.

## Sites where the distinction bites

Holiday accommodation is the classic case. A rural cottage may have a private supply, intermittent occupation and showers used by guests who know nothing about the system. The private-water regime tells you how the source is assessed. The Legionella assessment tells you how the property is flushed before guests arrive and how storage and showers are controlled.

Farm cottages and estates create another problem: one source may feed several dwellings or business units. The private-water risk assessment may describe the shared source, but each building still needs a view of its own hot and cold system. A safe borehole does not make every cylinder and outlet safe.

Seasonal sites add time. Campsites, glamping pods, visitor centres and remote cabins may stand unused for months. Reopening then becomes a water-system recommissioning task, not just a private-water sampling task.

The record trail should show both sides. Keep the private-water source assessment, treatment-unit service records and sampling correspondence in one place; keep the Legionella assessment, outlet list, temperature checks and flushing records in the same compliance file or clearly cross-referenced. The gap to avoid is a manager producing one folder confidently while the other duty has never been assessed.

## FAQ

### Does a private-water risk assessment include Legionella?

Not in the way a duty holder usually needs. It assesses source-to-tap drinking-water risk under the relevant private-water regime. Legionella control for hot and cold water systems still needs a building-side risk assessment, control scheme and records [6].

### Is borehole water more dangerous for Legionella than mains water?

The source alone is rarely the whole issue. The risk rises when water is stored, warmed, stagnates and is aerosolised. Private supplies can add sediment, treatment and storage complexities, so the building assessment should pay close attention to tanks, filters, dead legs and showers.

### Which regulator should an off-mains site contact?

For private-water supply questions, start with the local authority or the national private-water route for the nation: DWI/local authority in England and Wales, local council/DWQR in Scotland, and DAERA/DWI NI in Northern Ireland [1][2][4][5]. For Legionella health-and-safety control, use HSE in Great Britain or HSENI in Northern Ireland [6][7].

## Next step

Put two documents side by side: the latest private-water supply record and the latest Legionella risk assessment. If one is missing, do not treat the other as a substitute. The more detailed England-focused page is [Legionella and private water supplies: boreholes, wells and the 2016 Regulations](https://legionella.io/articles/legionella-and-private-water-supplies-boreholes-wells-and-the-2016-regulations/).

## Sources

[1] Drinking Water Inspectorate, "Drinking Water 2024: private water supplies in England - introduction". https://www.dwi.gov.uk/what-we-do/annual-report/drinking-water-2024/drinking-water-2024-private-water-supplies-in-england/introduction/
[2] Drinking Water Inspectorate, "Private Supply Legislation". https://www.dwi.gov.uk/private-water-supplies/legislation-pws/
[3] Drinking Water Inspectorate, "Drinking Water 2024: private water supplies in Wales - introduction". https://www.dwi.gov.uk/what-we-do/annual-report/drinking-water-2024/drinking-water-2024-private-water-supplies-in-wales/introduction/
[4] mygov.scot, "Registering, risk assessing and testing private water supplies". https://www.mygov.scot/private-water-supplies/register-test-assess
[5] DAERA, "Private Water Supplies". https://www.daera-ni.gov.uk/articles/private-water-supplies
[6] HSE, "Legionnaires' disease - what you must do". https://www.hse.gov.uk/legionnaires/what-you-must-do/index.htm
[7] Health and Safety Executive for Northern Ireland, "Legionella". https://www.hseni.gov.uk/topics/legionella