Guidelines for control of Legionella

Warm Water Systems

The maintenance requirements for warm water systems are set out in regulation 13 of the Legionella Regulations.
Temperatures should be monitored at the most distal outlet and at a range of outlets randomly selected within the system (the number will depend on the size and design of the system).
The intent of this monitoring is to measure the temperature at the key outlets in order to detect any temperature changes over time and throughout the system.
If relatively low temperatures are indicated in any area of a warm water system, the area should be investigated for evidence of poor water flow or stagnation.
All warm water outlets are not frequently used should be flushed weekly at full flow for at least 15 seconds and all outlets on individual branches should be flushed simultaneously.
System requires flushing six monthly using a chlorine solution or pasteurisation.

Hot water systems should be inspected at least once every month and the temperature of water stored in a storage water heater container (which must be at least 60°C) and at outlets should be measured.
All outlets that are not frequently used should be flushed weekly at full flow for at least 15 seconds.

At least once in every 12 months temperature control devices such as thermostatic mixing valves or tempering valves should be:

Maintained and serviced as recommended by the manufacturer and set out in AS 4032.
Disinfected (for example, using a chlorine solution or pasteurisation) before being returned to service.