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# Legionella Risk Assessment: UK Landlord & Business Guide (2026)
- URL: https://www.logbook.co.uk/legionella-risk-assessment-uk-landlord-business-guide/
- Published: 2026-06-08T15:31:25.000Z
- Updated: 2026-09-08T12:18:36.000Z
- Description: Legionella risk assessment is a legal duty for UK landlords and businesses under the HSE L8 ACoP. What it covers, who must do it, review frequency, and the records you must keep.
- Author: Jamie Dawson
- Tags: Water Hygiene Logbooks

> **Quick answer:** UK landlords and businesses have a legal duty to assess and control legionella risk under the Health and Safety at Work Act, COSHH, and the HSE's L8 Approved Code of Practice (ACoP). A legionella risk assessment identifies where the bacteria could grow in a water system and what controls are needed. For simple domestic rentals, a competent landlord can often assess themselves; complex systems need a professional. Records (the assessment, monitoring, and reviews) must be kept. Non-compliance risks unlimited fines and prosecution.

## The legal duty

Legionella control is governed by:

- **Health and Safety at Work Act 1974**: general duty of care
- **Control of Substances Hazardous to Health (COSHH) 2002**: legionella bacteria are a hazardous substance
- **HSE L8 Approved Code of Practice**: "Legionnaires' disease: The control of legionella bacteria in water systems"
- **HSG274**: supporting technical guidance

Landlords are explicitly included, the HSE confirms residential landlords have a duty to assess and control legionella risk for their tenants.

## What legionella is and why it matters

Legionella bacteria cause Legionnaires' disease, a potentially fatal pneumonia. They thrive in water systems between 20-45°C, especially where water stagnates, where there's sediment/scale, and where it can be aerosolised (showers, taps, cooling towers). The risk assessment is about identifying and removing these conditions.

## What the risk assessment covers

- Identifying the water system (tanks, pipes, outlets, water heaters)
- Water temperatures (hot stored ≥60°C, distributed ≥50°C; cold ≤20°C)
- Stagnation points (infrequently used outlets, dead legs in pipework)
- Sediment, scale, and biofilm risk
- Aerosol-generating outlets (showers, spray taps)
- Vulnerable occupants (elderly, immunocompromised, higher risk)
- Required control measures

## Control measures

- Keep hot water hot (≥60°C in storage) and cold water cold (≤20°C)
- Flush infrequently-used outlets weekly
- Remove dead legs and redundant pipework
- Descale and clean shower heads periodically
- Keep tanks covered and clean
- Monitor temperatures

## Domestic rentals vs complex systems

**Simple domestic rentals** (typical houses/flats with combi boilers or small systems): a competent landlord can usually assess themselves using HSE guidance. The assessment is often simple and may conclude the risk is low with basic controls (flushing after void periods, etc.).

**Complex systems** (large buildings, cooling towers, care homes, HMOs, commercial premises, stored hot water with multiple outlets): require a competent person (often a specialist water hygiene contractor) and a written control scheme.

## How often to review

The assessment must be reviewed "regularly" and whenever it may no longer be valid:

- Domestic rentals: typically every 2 years
- When the water system changes
- When occupancy or use changes
- After void periods (water stagnation)
- If a case of Legionnaires' disease is linked to the property

## Records you must keep

- The written risk assessment
- Control scheme (for higher-risk systems)
- Temperature monitoring logs
- Flushing records (void periods, little-used outlets)
- Tank inspection and cleaning records
- Review dates and any remedial actions

See our [temperature monitoring log guide](https://www.logbook.co.uk/legionella-temperature-monitoring-log-uk/) and [L8 ACoP compliance guide](https://www.logbook.co.uk/water-hygiene-records-l8-acop-compliance-uk/).

## Common landlord mistakes

1. Believing legionella doesn't apply to domestic rentals (it does)
2. Paying for an expensive certificate when a simple self-assessment suffices for low-risk systems
3. Not flushing the system after void periods between tenancies
4. No records, assessment done but never documented
5. Never reviewing the assessment

## FAQs

### Is there a "legionella certificate" landlords must have?

No statutory certificate exists, the requirement is a risk assessment, not a certificate. Beware companies selling unnecessary "legionella certificates" for simple domestic properties; a documented self-assessment often suffices.

### How much does a professional legionella assessment cost?

£75-£200 for a domestic rental; more for complex commercial systems. Many landlords self-assess simple properties for free using HSE guidance.

### Does a combi boiler reduce legionella risk?

Yes, combi systems with no stored water and no large tanks are lower-risk because there's less stagnation. The assessment is correspondingly simpler.

### What temperature kills legionella?

Legionella is killed rapidly above 60°C. Hot water should be stored at ≥60°C and distributed at ≥50°C; cold water kept below 20°C.

## Related guides

- [Legionella risk assessment: landlord & business guide](https://www.logbook.co.uk/legionella-risk-assessment-uk-landlord-business-guide/)
- [Legionella temperature monitoring log](https://www.logbook.co.uk/legionella-temperature-monitoring-log-uk/)
- [Water hygiene records: L8 ACoP compliance](https://www.logbook.co.uk/water-hygiene-records-l8-acop-compliance-uk/)

*Last reviewed 2026-06-08 by Jamie Dawson, Editor.*

*Free download: spa pools and hot tubs carry a materially higher legionella risk than a main pool. Our* [*pool and spa water test log template*](https://www.logbook.co.uk/pool-water-test-log-template/) *covers the daily monitoring.*