Routine checks and maintenance logs

Why keep a log

Control of Legionella and the good order of a cold water system depend on routine checks that are recorded, so trends are visible and gaps are obvious. A maintenance log records the checks, results and actions for review. A completed entry supports traceability, but it does not show that the check was done correctly or that all controls still work. Compare the records with current measurements and the condition of the system.

Typical routine checks

• Temperature monitoring at representative, or sentinel, outlets: check that cold water falls below 20°C within two minutes. The nearest and furthest taps are typical sentinel points; complex branches, zones or floors can need additional locations.
• Inspecting storage cisterns periodically for cleanliness, secure covers, screens and any sign of contamination.
• Checking that infrequently used outlets are being flushed.
• Inspecting and servicing controls such as pressure-reducing valves, and any thermostatic mixing valves where fitted.
• Checking for leaks, corrosion and other defects.

Records and review

Record each check with the date, the reading or result, and any action taken. Review the records so a problem such as a slowly rising cold water temperature is caught early. Keep documentation from commissioning, including test and disinfection records, with the log.

Monitoring frequencies and the exact items come from the risk assessment and HSE guidance. Confirm them against HSG274 and the L8 Approved Code of Practice, not from memory.

Frequencies in HSE's checklist

HSE's guidance (HSG274 Part 2) gives these routine checks for cold water systems; a risk assessment can set shorter intervals:

• Monthly: run the cold sentinel taps, normally those nearest to and furthest from the cold water tank, and confirm the water falls below 20°C within two minutes. Watch the thermometer throughout, because heat gain may not show after one minute.
• Weekly: use or flush little-used outlets under the assessed programme, allowing the temperature to stabilise and become comparable with the supply. Record the action and any problem, and control exposure to spray while flushing. Higher risk or susceptible users can require more frequent attention; keep the routine going once it starts.
• Quarterly: dismantle, clean and descale showerheads, spray taps and hoses, or more often if they foul quickly.
• Annually: inspect the cold water storage tank inside and out, and check the stored water temperature, away from the float valve, with the incoming mains temperature. Take that reading in summer, when water is warmest, or at the frequency temperature profiling shows is needed.