Water

Legionella control and ACoP L8 explained

5 min read · Updated 11 June 2026

The Approved Code of Practice L8 and the guidance in HSG274 require duty holders to assess and control the risk of legionella bacteria in their water systems.

The legionella risk assessment

A competent person assesses the water system, how it is used and where conditions could allow legionella to grow, following BS 8580 and HSG274. The assessment is kept under review, especially after any change to the system.

The written scheme of control

  • Sentinel outlet temperature monitoring, typically monthly
  • Calorifier and storage tank checks on defined cycles
  • Flushing of little-used outlets
  • TMV servicing at least annually
  • Records kept to demonstrate control

Who is responsible?

The duty holder must appoint a competent responsible person to manage the scheme, and ensure everyone carrying out the work is suitably informed, instructed and trained.

Evidencing control on CertFlow

CertFlow turns the L8 cycle into recurring tasks, captures temperatures and flushing on mobile, and keeps the risk assessment and the full monitoring history searchable and exportable for an audit.

References

Sources & official guidance

Links to primary UK legislation and official regulator guidance. CertFlow is independent and not affiliated with these bodies.

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