A compliant Legionella logbook is not a diary of temperatures. It is the evidence that a named person decided what to control, set out how, and can prove it was done. If a stranger opened your folder tomorrow, every reading should trace back to a specific outlet, a date, a person, and a documented response when something fell out of range.

Most logbooks fail not because the readings are missing but because the structure around them is. There is no asset register to say which outlets should have been checked, no written scheme to say what “in range” means, and no remedial trail to show what happened when a tap ran cold.

So here is the full structure, section by section, that you can copy into a binder or rebuild in software. Treat it as a template, not gospel: your risk assessment decides what actually belongs in yours.

Why the sections matter more than the readings

L8 expects duty holders to keep records of the precautions taken, the monitoring carried out, and the management arrangements behind them [1]. That is three different kinds of record, and a logbook that is all monitoring and no management arrangements is only doing a third of the job.

The sections below map onto that expectation. The front of the book establishes responsibility and scope. The middle holds the live monitoring. The back proves you reacted when control slipped. Skip the front and back, and a perfect run of temperatures proves very little, because nobody can tell what was supposed to be checked or what happened when it wasn’t right. covers why record keeping exists in the first place; this article is about exactly what goes in.

The logbook template, section by section

Build these as labelled tabs or dividers. Each one is a section, not a single page, and most will grow over time.

Front matter and responsibility:

  • Record the site address, building reference, and the responsible person or duty holder by name, with the date they took the role.
  • List the competent persons and contractors involved, what each is appointed to do, and their Legionella Control Association membership or equivalent.
  • Hold a current copy of, or a clear reference to, the written scheme of control so anyone reading knows the limits and frequencies that apply here.

System description and assets:

  • Keep an up-to-date asset register: every calorifier, cold water storage tank, TMV, sentinel outlet, shower, and known dead leg, each with a unique reference.
  • Hold the system schematic, marked with sentinel points and any areas of higher risk.
  • Note the date of the current Legionella risk assessment and when the next review is due.

Routine monitoring logs:

  • Log monthly hot and cold water temperatures at sentinel outlets, with the asset reference, reading, date, and initials [3].
  • Record calorifier flow and return temperatures, and any drain-down or inspection.
  • Log weekly flushing of little-used outlets, with the outlets named rather than counted.
  • Record cold water storage tank temperatures and visual inspections.
  • Log TMV servicing, showerhead cleaning and descaling, and any chlorination or tank clean.

Periodic and specialist checks:

  • Record sampling results where your scheme calls for them, with dates and the analysing laboratory.
  • Log the annual review of the risk assessment and the written scheme.
  • Hold certificates and reports from contractor visits, tank cleans, and disinfections.

Remedial actions and exceptions:

  • For every out-of-range result, record what was found, who was informed, the action taken, the re-check, and the close-out date.
  • Keep correspondence about defects, repairs, and any temporary control measures.

Review and sign-off:

  • Record the responsible person’s periodic review of the records, signed and dated.
  • Note any management meetings where water hygiene was discussed and decisions made.

How to use and record it

The frequencies and limits are not for you to invent. Sentinel temperature checks, flushing intervals, and sampling are set by your site risk assessment and the written scheme, not by a default printed in a template [2]. The HSE position on hot and cold water gives you the general expectation, but the figure that governs a given outlet is the one your competent person recorded for it [3].

Record at the point of the check, not at the desk afterwards. A column of readings all dated the last Friday of the month, entered in one sitting, tells an investigator more than you would like. Name the person who did the work, not just the company. And when a reading is wrong, the most important entry in the whole book is the one that comes next: the remedial section is what turns a number into evidence of a managed control.

The sections people skip

Three sections go missing again and again, and they are always the ones that matter under scrutiny.

The first is the written scheme of control. Without it, nobody reading the book knows what the readings are being judged against, so a row of figures floats free of any standard. sets out the essential records that hold compliance together, and the scheme is the spine of all of them.

The second is the remedial trail. Plenty of logbooks faithfully record that an outlet ran below temperature and then say nothing more. A finding with no follow-up reads as a control you noticed and ignored.

The third is the responsible person’s sign-off. Monitoring that nobody senior ever reviews is monitoring that nobody owns. A dated signature against a periodic review is small to add and disproportionately reassuring to an inspector.

Manual binder or auto-maintained record

The template is identical whichever way you keep it. What differs is how the gaps show up.

A paper binder relies on someone noticing that an outlet was missed, that a remedial was never closed, or that a contractor certificate never made it into the tab. Nobody notices until the audit. A digital logbook can hold the same sections and flag the gap as it happens: a sentinel check that came due and wasn’t done, an exception raised but never closed, a timestamp that doesn’t match the working day. Tools such as L8log are built around exactly these sections, so the asset register, the temperature logs, the remedial trail, and the sign-off stay linked rather than living in separate piles. walks through setting one up.

The pragmatic call: keep paper if your site is small and your discipline is good, but once you manage several buildings, an auto-maintained structure stops missed sections becoming silent ones.

This is general guidance to help you build a complete logbook, not a substitute for a competent, site-specific risk assessment. The sections you actually need, the limits you record against, and the frequencies you follow all come from that assessment and a competent person who knows your system. Use this template as a checklist for completeness, then let your scheme set the figures.

A practical first step today: print the section list above and walk it against your current logbook, one tab at a time. Wherever a section is thin or missing, you have found your next job, before an inspector does.

FAQ

Do I need a separate logbook for each building?

Usually, yes. Each building has its own assets, schematic, and risk assessment, so a single shared book quickly becomes ambiguous about which outlet was checked where. Keep a distinct record per site or building reference. A digital system can hold them all under one account while keeping each building’s asset register and logs cleanly separated, which is harder to manage with shared paper folders.

Is a blank shop-bought logbook template enough to be compliant?

A blank template gives you the right sections, which is a good start, but it is not compliance on its own. It only becomes compliant once it is populated with your asset register, your written scheme of control, and monitoring carried out at the frequencies your risk assessment sets [1][2]. A pristine pre-printed book with empty remedial and sign-off sections is the opposite of reassuring.

How long do I keep completed logbook records?

Retention is set by HSE guidance rather than by the format you use [1]. Confirm the current period for your records and file completed logs accordingly rather than discarding them when a book fills up. If you move from paper to digital, the old records still carry the history and the retention clock keeps running on them.

Sources

[1] HSE, “Legionnaires’ disease. The control of legionella bacteria in water systems - Approved Code of Practice and guidance (L8)”. https://www.hse.gov.uk/pubns/books/l8.htm [2] HSE, “Legionnaires’ disease: Technical guidance (HSG274)”. https://www.hse.gov.uk/pubns/books/hsg274.htm [3] HSE, “Hot and cold water systems”. https://www.hse.gov.uk/legionnaires/hot-and-cold.htm