A high priority in any system is water temperature. As we have already covered, Legionella grows best in temperatures between 20 – 45°C. This means that maintaining outlet temperatures outside of this bracket is vital. For this reason ACoP L8 recommends that hot water should be stored at 60°C and should reach a temperature of 50°C after running for 1 minute from an outlet. This recommendation does not apply if biocides are in use in a water system (more information on biocides will follow), however the HTM 04- 01 suggests that temperature management should be a priority even when biocides are being used and we would have to agree that having as many preventative measures as possible is always the best option. For hot water, the risk of scalding must also be taken into consideration and 50°C is considered the safest temperature. For cold water outlets the temperature should be below 20°C after running the water for 2 minutes.
Certain sites may have outlets that are used infrequently such as showers or taps and we would recommend that these are removed. However there are procedures in place for sites where, for whatever reason, these outlets are still in place. As well as monitoring the temperature of these showers and taps they must also be flushed to reduce the risk of Legionella growing in peripheral parts of the system. ACoP L8 recommends weekly flushing of these outlets and HTM 04- 01 suggests that flushing twice a week is the best way to manage the risk of such outlets.