Legionella logbook requirements

"The logbook" sounds like a single dusty binder, and on plenty of sites it still is one. What ACoP L8 actually requires is a records system — and the difference between a logbook that satisfies an auditor and one that doesn't is rarely what was recorded. It's whether the record can be found, trusted and produced.

The logbook is a records system, not a book

L8's record-keeping expectations attach to the compliance programme, not to a physical object. Whether it lives in a binder, a shared drive or a platform, the same tests apply: complete, contemporaneous, attributable, retrievable. The binder fails most often on the last one; the shared drive on the first.

What goes in it, item by item

• The current risk assessment (or a reference to it), with its review history.
• The written scheme of control for each system — see our guide to what that must contain.
• Monitoring results — every temperature run, every flush of a little-used outlet, every inspection, with date, point and person.
• Remedial actions — what was found, what was done, and evidence of closure. An open defect with no closure record is an audit finding waiting to be written.
• Cleaning and disinfection certificates — tank cleans, calorifier work, chlorination records.
• Laboratory reports — sampling results, including the chain from sample to result to any action a positive triggered.
• Training and competence records for the people named in the scheme.

How long it all has to survive

Monitoring and inspection records: at least five years. The risk assessment and written scheme: while current, plus two years after they're superseded. Five years is also the LCA's expectation for service providers' records — so for a water-treatment contractor, five years is simply the floor. The practical implication: whatever holds your logbook has to survive staff churn, office moves and IT migrations without losing a page.

The 25–42°C band, and what monitoring proves

Legionella multiplies in warm water — roughly 20–45°C, most happily around 25–42°C. Control regimes are built to keep water out of that band: cold below 20°C, hot stored at 60°C and arriving at outlets above 50°C. Your monthly sentinel temperatures aren't a ritual; they're the proof the system spends its life outside the growth zone. Which is why gaps in the temperature record read so badly in an audit — a missing month isn't missing paperwork, it's a month nobody can prove the water was safe.

Digital logbooks

The auditor's tests — complete, contemporaneous, attributable, retrievable — are exactly what digital records do well: entries timestamped at capture, authorship automatic, search instant, and an audit trail paper can't offer. The capture point matters most: records created on site, at the asset, don't suffer the transcription drift that retyping introduces, and lab results that flow into the same system close the loop from sample to logbook. The records library then has one job: five years, findable in seconds.