Legionella Management in Hot and Cold water Systems.
Legionella is naturally present in all water systems both natural and man made. With the right environmental conditions, Legionella bacterica can replicate to dangerous levels. The risk of elevated Legionella bacteria levels can occur where:
- The a water temperature is between 20–45 °C
- The contaminated water is expelled as breathable droplets, e.g. aerosol created by a cooling tower, or water outlets
- Water is stored and / or re-circulates water
- The system contains a source of nutrients for the organism to grow, e.g. rust, sludge, scale, organic matter and biofilms.
The most common sources of Legionella are in man-made water systems including:
- Cooling tower and evaporative condensers
- Hot and cold water systems.
- Spa Pools
There are also a number of other systems that pose a potential risk to legionella exposure of elevated levels these include but are not limited too: humidifiers, air washers, emergency showers, indoor ornamental fountains etc. If you are an employer, or someone in control of premises (e.g. landlord), you have a duty to understand and manage all the Legionella risks on the premises. For further information, please contact Environmental Inspection.
All hot and cold water systems in rented, commercial and industrial premises must have a legionella risk assessment. Not all systems will require elaborate control measures. A simple risk assessment may show that the risks are low and being properly managed to comply with the law. In such cases, your assessment may be complete and you may not need to take any further action, however, it is important to review your assessment if any works are undertaken on the hot and cold water system or good practice at least every two years.