Legionella Risk Calculator

Answer 5 simple questions to instantly estimate your baseline Legionella risk profile and see if you legally require an ACoP L8 assessment.

Property Risk Profile

Certain environments hold higher risk due to vulnerable occupants or complex plumbing.

Stored water allows sediment to build up, acting as a food source for bacteria.

Legionnaires' disease is contracted by inhaling aerosolised water droplets.

Stagnant water is the leading cause of Legionella proliferation.

Legionella thrives between 20°C and 45°C.

Your Estimated Risk Profile

LOW RISK

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Legal Disclaimer & Indemnity This calculator is provided by Safety Certificates UK for educational and preliminary informational purposes only. The output generated by this tool does not constitute a formal, "suitable and sufficient" Legionella Risk Assessment as required by the Health and Safety at Work etc. Act 1974, COSHH Regulations 2002, or the HSE ACoP L8 guidelines.

The results are based solely on unverified user inputs and cannot account for all site-specific technical variables, structural defects, or complex plumbing systems. Safety Certificates UK, its partners, and its assessors accept zero liability for any injury, illness, legal action, financial loss, or enforcement notices arising from actions taken, or not taken, in reliance upon this calculator. To fulfil your statutory duties as a Duty Holder, a formal, physical risk assessment must be carried out by a competent person.

How does the Calculator Work?

Our algorithm is built directly upon the risk factors outlined in the Health and Safety Executive's HSG274 technical guidance. It evaluates the four primary pillars of water hygiene risk:

  • System Complexity: The presence of storage tanks or complex pipework that encourages biofilm growth.
  • Aerosolisation: The physical mechanism by which the bacteria can be inhaled (showers, cooling towers).
  • Stagnation: How often water is refreshed to prevent bacterial proliferation.
  • Temperature: Whether your system falls within the highly dangerous proliferation zone.
While this tool gives you a strong indication of your risk level, remember that under UK law, you cannot solely rely on self-assessment software. A competent person must physically audit the site.