- Requirement of contract - often prior to hand over a new building or following modification of existing pipe work the client will ask
for disinfection of the relevant services and supply of a chlorination certificate.
- Following a period of non-use. The HSE recommend that all hot and cold water services that are not in continuous use should be flushed weekly. Where
this is not followed it is good practice to chlorinate before use.
- After contamination of a water system. This maybe after widespread detection of legionella bacteria, a burst
pipe or post contamination event (such as dead animal in water tank).
- Prior to occupation of a dwelling if voided for over a week and not regularly flushed.