Most legionella problems come from the same handful of faults. Each one is straightforward to fix once it has been found. These are the six that turn up most often in legionella risk assessments.
1. Hot water that is not hot enough
Thermostats get turned down to save energy, leaving stored water in the range where legionella grows. Fix: store hot water at 60°C or above, where the bacteria are killed within minutes, and check the temperature regularly.
2. Cold water that is too warm
Tanks in hot roof spaces and cold pipes running beside hot ones push cold water above 20°C. Fix: insulate tanks and pipes, and check that the tank is not oversized for the building, so water does not sit in it for long.
3. Outlets nobody uses
Spare bedrooms, disabled toilets, cleaners’ sinks and outside taps can go weeks without being run. Fix: flush them on a set schedule, typically weekly, and record it. Remove outlets that are no longer needed.
4. Dead legs
Old alterations leave capped pipes full of standing water. Fix: cut dead legs back to the main pipe.
5. Dirty storage tanks
Missing lids, sediment and debris give bacteria the nutrients they need. Fix: fit a close-fitting lid, inspect the tank, and clean and disinfect it when needed.
6. No records
Checks may be happening, but if nothing is written down you cannot show it. Fix: keep a simple log of temperatures, flushing and cleaning, with dates and names.
Do not forget shower heads
Scale and biofilm build up inside shower heads and hoses, and showers create exactly the fine spray that carries legionella. Clean, descale and disinfect them regularly.
How to find out which apply to you
A legionella risk assessment checks your system for all of these and ranks what it finds by priority. National guidelines recommend reviewing it at least once a year. Our guide to water temperatures for legionella control explains the numbers in more detail.
Safer Solutions provides legionella risk assessments, sampling and water tank cleaning across Ireland. Call 086 275 9728, email info@safersolutions.ie or request a quote.