Legionella bacteria will thrive in water temperatures between 20°C- 46°C, their numbers increase most rapidly between 35°C- 40°C.
Where you take the test determines what sort of information the results tell us, for instance:
- Direct Fed Outlets
A clear results shows that water to the outlet and the tap itself are free from legionella.
- Sentinel Outlets
Taking samples from the nearest & furthest outlets will indicate if the bulk of the hot water distribution systems has any legionella present.
Schools, hospitals and care homes install TMVs (Thermostatic Mixer Valves) just prior to the hot outlets to provide a safe water temperature for the service users. It is not uncommon for legionella to thrive within the TMV and give a positive result, this does not necessarily mean all you hot water is contaminated with legionella.
