Recommissioning Water Systems following a site shutdown

There is potential for multiple outbreaks of Legionnaires’ disease following the COVID-19 outbreak if actions taken now are not carefully considered. The responsibility for legionella control lies with the Dutyholder. For more information please contact Primary Water Solutions for assistance during this period and we will be happy to assist where needed:

When buildings reopen following the lifting of COVID-19 restrictions, it is essential that water systems are not simply put straight back into use.

For small, simple hot and cold water systems PWS would be recommending flushing through with fresh mains water and testing the system post flushing procedure implementation.

Larger buildings such as those with tanks, showers, calorifiers and more complex pipework, it is likely to be for more extensive flushing followed by cleaning and disinfection and followed up with sampling to prove efficacy of disinfection procedure.

In all cases where systems are being recommissioned it is sensible to have evidence to prove/reassure that the recommissioning process has been effective. Sampling to BS7592 should be considered for recommissioning plans to validate the effectiveness of the process.

As per HSG274 part 2, samples should be taken 2-7 days following recommissioning and not on the day of disinfection. Follow up samples may need to be considered as part of the recommissioning plan.

During the potential warmer months, it is likely that some increase in bacteria levels and biofilm will occur and it may become apparent that a simple disinfection at 50ppm of chlorine for an hour may not be successful. Be prepared that the need to repeat some disinfection’s to achieve success may occur.

Above actions are examples of what may be suitable for these types of sites and systems, I would treat building/occupier systems on a case by case basis.

For further information – contact us via our website or on Tel: 01454 501818