ACoP L8 is the HSE Approved Code of Practice for controlling legionella in water systems in the UK. It sets out the legal duties of employers and those in control of premises.

HSG274 is HSE technical guidance that explains how to control legionella in evaporative cooling, hot and cold water and other systems. It covers temperatures, flushing and monitoring.

What temperature should hot water be stored at for legionella control?

HSG274 guidance is to store hot water at 60°C and reach at least 50°C at outlets within a minute. Check the current edition for healthcare settings and details.

How does Aqueduct help with legionella control?

Aqueduct records outlet temperatures and flow continuously and flags out of range readings. The responsible person runs the control scheme and acts on alerts.

Glossary

Water standards and regulation

What is Legionella and HSG274 / ACoP L8?

Definition

Legionella and HSG274 / ACoP L8 refers to the UK framework for controlling legionella bacteria in water systems. The Approved Code of Practice L8 sets out legal duties, and HSE technical guidance HSG274 explains how to control risk through temperature control, flushing, monitoring and record keeping.

What it is

Legionella bacteria can grow in water systems where temperatures allow and water stagnates, causing Legionnaires' disease. Under UK health and safety law, employers and those in control of premises must assess and control the risk. ACoP L8 describes the duties, including a risk assessment, a written control scheme and an appointed responsible person.

HSG274 gives the technical detail. For hot and cold water systems, temperature is the usual control. The guidance sets targets such as storing hot water at 60°C, reaching at least 50°C at outlets within a minute, and keeping cold water below 20°C. Little-used outlets are flushed regularly. Check the current edition for full detail and healthcare variations.

Who it applies to / where it is used

The framework applies across UK workplaces and premises with water systems, including offices, hospitals, care homes, hotels, schools, leisure centers and industrial sites. Facility managers and water hygiene contractors carry out much of the monitoring.

How it is measured / what evidence it needs

Inspectors expect records that show the control scheme is working, not only that checks were planned.

A current legionella risk assessment
Temperature checks at sentinel outlets and calorifiers
Flushing records for little-used outlets
Records of remedial actions
Records kept for the required period

How Aqueduct helps

Aqueduct records temperature and flow at outlets continuously, with the audit trail duty holders need. The responsible person keeps the control scheme.

Continuous outlet and calorifier temperatures, rather than manual monthly readings
Flow sensing that shows when outlets were actually used or flushed
Alerts when temperatures leave the safe band, routed into the CMMS
Exportable records through aQ Assurance for inspection