Legionella control and maintenance records

Monitor the whole control regime

Water-temperature checks show conditions at the measured points only, not across the whole hot-water system. Use the risk assessment and control scheme to choose the checks, locations, intervals and corrective actions.

Routine measures

• Storage and circulation. For the conventional temperature regime, verify at least 60 °C from storage and the specified circulation return temperature, normally at least 50 °C in the general regime.
• Distribution. Check the relevant hot outlets for at least 50 °C within one minute, or 55 °C in healthcare premises. With a TMV, take this measurement at the hot inlet. Check the blended outlet separately against its scald-control setting.
• Sentinels and other outlets. Sentinel points include the nearest and furthest outlets in a simple system; complex systems need points chosen to represent their separate loops and branches. Include other representative outlets on a rotation that covers the system.
• Stagnation and cleanliness. Remove unnecessary pipework, manage little-used outlets, and clean, descale and disinfect showerheads and hoses at the required intervals.

Records and action

Record actual readings, test results, flushing, cleaning and any failure or remedial work. A recorded low temperature needs investigation and correction; merely completing the log does not restore control. Keep the assessment and monitoring records appropriate to the premises and applicable duties. The checks for a large managed building should not be presented as an identical mandatory schedule for every owner-occupied home.

Maintain TMVs and the outlet protections alongside Legionella controls. Neither a cylinder temperature entry nor a successful TMV test is a complete system assessment.

What the records show, and for how long

• Record each TMV’s measured set temperature and later checks, including the test conditions, failures and remedial action. Comparison can reveal drift, but records do not guarantee that every failure will be found before an injury.
• Log the cylinder and branch return temperatures, balancing settings, and pump and permitted-schedule checks. Comparing visits can reveal a trend that needs investigation; each entry is evidence of the conditions actually checked.
• HSE's guidance keeps records of monitoring, inspections, tests and checks, with their dates, for at least five years. Other records, such as the risk assessment and the written control scheme, are kept while current and for at least two years afterwards.