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Compliance

Legionella in the Workplace: Does Every Business Need a Risk Assessment?

If you employ people, or control premises that others use, legionella is part of your health and safety duties. Here is what that means in practice.
5 min read · Updated October 2026

Who has the duty

Employers, self-employed people and anyone in control of premises must assess and control the risk from legionella. There is no minimum number of employees for this duty: a small shop or office with a kitchen and toilets is included, although the assessment can be simple.

Does it have to be written down?

If you have five or more employees, you must record the significant findings of your risk assessment. Below that, recording is still strongly recommended because it is the easiest way to show you have done it.

What a workplace assessment covers

  • Hot and cold water systems, including water heaters and tanks
  • Showers, including emergency showers and eye wash stations
  • Little-used outlets and dead legs
  • Any cooling towers, spa pools or humidifiers
  • Who is at risk, including visitors and vulnerable people
  • Who is the responsible person and how checks are recorded

Who enforces

Local authority environmental health teams usually cover offices, shops, hotels, restaurants and leisure premises. HSE usually covers factories, warehouses, hospitals, schools and premises run by local authorities. In Northern Ireland, HSENI and district councils share the role.

Frequently asked questions

Does a small business need a legionella risk assessment?

Yes. The duty applies to all employers and people in control of premises. For a small, simple building the assessment can be short.

Do I need a legionella risk assessment with fewer than five employees?

You still need to assess the risk. The legal requirement to write down the significant findings applies when you have five or more employees.

Disclaimer: This guide is general information about UK requirements and is not legal advice. Always check the current legislation and guidance for your premises.