You have a positive Legionella sample
A laboratory has reported Legionella in your water. What happens next depends on the count and how many outlets it shows up at. Work through the immediate steps, then investigate the cause.
Do this now
- 1Confirm the count and which outlets it came from, and check it against the action levels before you act.
- 2Tell your Responsible Person and competent help immediately; do not brief staff or the public with speculation.
- 3Do not disinfect or flush before any further sampling unless your competent advisor tells you to, it can destroy the evidence of the cause.
- 4Pull together the risk assessment, recent temperature and monitoring records, and any recent changes to the system.
- 5Agree the remedial action and resampling plan, and record every decision and who made it.
Tools to use
Read next
- History of Legionella and major outbreaks
- What to do if you get a positive Legionella test
- Case study: outbreak caused by a poorly maintained cooling tower
- Learning from past Legionella outbreaks in the UK
- Understanding lab results: CFU counts and what they mean
- Scientific analysis of a Legionella outbreak
Keep this under control
Turn these steps into a managed routine with records that hold up to scrutiny.
Cite this page
"You have a positive Legionella sample." Legionella.io. https://legionella.io/situations/positive-legionella-sample/
Free to reuse under CC BY 4.0: quote, adapt or republish with attribution and a link back to the original.