One of the important controls for Legionnaire's Disease is that cold water, within our buildings' water systems, remains cold (less than 20oC), and we may have advised you to monitor this as part of your monthly control routine.
It's become apparent in the current heatwaves, that mains cold water has been found to be above 20oC, which means that once it's past your water meter, you're stuck with it at that temeperature!
Additionally, cold water tanks, especially in roof spaces can get quite hot in this weather, again there can be little you can do about this.
To mitigate this, we're advising all clients to make sure that all your other controls that are relevant to cold water are in good order, as it takes the cumulative effect of all of these factors to create a significant legionella risk. These are;
- any small cold-water tanks are well lagged, to try and prevent further heat gain from a hot roof space;
- all cold-water tanks are in good condition, i.e. not affected by limescale/silt, and especially any biofilm (slimy bacterial growth);
- flushing through of any little, or unused outlets is up to date. Indeed, you may wish to increase the frequency and duration of flushing through of cold-water systems as an extra precaution; and
- that all outlets, shower heads particulaly, are clean and limescale-free.
If you're really worried about the extra risk during this weather (for instance if your water services might affect a higher-risk groups of people), water sampling and analysis is an option as a final means of assurance. We can help you with this if you wish, so please do get in touch if this is something you'd like to explore.