A Legionella risk assessment (also known as a water hygiene risk assessment) is an evaluation of your water systems to identify and manage the risk of Legionella bacteria growth and spread. It’s required under UK legislation such as the Health and Safety at Work etc. Act 1974, the Control of Substances Hazardous to Health (COSHH) Regulations 2002, and relevant guidance including ACoP L8 and HSG274.

At Ark, our specialists conduct detailed assessments to ensure your water systems are safe, compliant, and backed by documented evidence.

The duty holder, often the building owner, landlord, facilities manager, or “person in control of premises”, is legally responsible for ensuring Legionella risk is managed. They may appoint a responsible person to take day-to-day control, but accountability cannot be delegated.

Ark acts as a trusted compliance partner: we can support or act as the responsible person, ensuring all obligations are met and documented.

There are a few types of survey / inspection approaches under Legionella/compliance frameworks:

  • Management Survey: a non-intrusive inspection of hot & cold water systems to locate and assess potential risks.
  • Refurbishment / Demolition Survey: required before works start, involving intrusive inspection to uncover hidden hazards (e.g. inside walls, pipework).
  • Monitoring & Testing: for systems where risk warrants it, periodic microbiological sampling in accordance with BS 7592 may be required.

Where necessary, Ark conducts intrusive inspections, material testing, temperature checks, and system checks to underpin compliance-ready management plans.

Review the risk assessment at least annually, or sooner if there are changes to system design, use, or if any control measure fails.

For systems such as cooling towers or open water systems, microbiological monitoring is often required quarterly or more frequently.

Hot & cold water systems generally require monitoring only where control regimes are in doubt or conditions indicate risk.

Ark integrates periodic inspection schedules into continuous compliance programmes, with alerts and recordkeeping via QUOODA®.

Failing to manage Legionella risk properly can result in:

 

  • Serious health hazards, including Legionnaires’ disease (which is notifiable in England and Wales)
  • Enforcement actions by the HSE or local authorities
  • Fines, legal liability, prosecution
  • Reputational damage and loss of stakeholder trust

At Ark, we bring over 30 years’ experience, deliver robust evidence chains, and support your compliance journey so exposure is minimised.