What goes on a legionella temperature monitoring sheet?
On this page
Key points
- The sheet has one row per reading: date, outlet, hot or cold, temperature, time to temperature, pass or fail, initials, and an action column for failures.
- Targets go in the header so nobody guesses: hot ≥50°C within 1 minute (55°C healthcare), cold <20°C within 2 minutes, calorifier flow ≥60°C.
- A failed reading is only half recorded until the action column says what was done about it.
- Keep completed sheets at least five years under ACOP L8, paper or digital.
- The sheet is a recording tool, an indicative starting point. It records; it never certifies the system as safe.
A legionella temperature monitoring sheet is a simple table: one row per reading, with the date, the outlet, the temperature reached, the time it took, whether it passed, who took it, and what was done if it failed. Used on the monthly round of sentinel outlets and calorifier checks, it turns "we keep an eye on the temperatures" into dated, initialled evidence. This page gives you the column set, a filled-in example, and the mistakes that make sheets worthless.
The columns the sheet needs
Strip a monitoring sheet down and eight columns do the work:
- Date the reading was taken.
- Outlet or asset — the name from your sentinel list or asset register, such as "Calorifier 1 flow" or "2nd floor basin, far end".
- Service — hot, cold, or calorifier flow/return.
- Temperature reached — the stabilised figure in °C.
- Time to temperature — how long the outlet took to stabilise.
- Pass / fail — against the target in the header, not against memory.
- Initials — who took the reading.
- Action taken — what happened next if it failed, or "none required".
The header carries the site name, the month covered, and the target figures, so the pass/fail column is a comparison, not an opinion: hot water 50°C or more within one minute (55°C in healthcare), cold below 20°C within two minutes, calorifier flow at least 60°C and return at least 50°C. The temperature chart sets out the full set of figures if you want them printed on the sheet itself.
A filled-in example
| Date | Outlet / asset | Service | Temp °C | Time | Pass? | Init. | Action taken |
|---|---|---|---|---|---|---|---|
| 03/08/2026 | Calorifier 1 flow | Hot flow | 61.2 | — | Pass | JT | None required |
| 03/08/2026 | Calorifier 1 return | Hot return | 52.4 | — | Pass | JT | None required |
| 03/08/2026 | Kitchen tap (nearest) | Hot | 53.8 | 25 s | Pass | JT | None required |
| 03/08/2026 | 2nd floor basin (furthest) | Hot | 47.9 | >60 s | Fail | JT | Reported to responsible person; TMV on that branch checked 05/08 and found scaled — serviced, retest 54.1°C |
| 03/08/2026 | Ground floor WC basin | Cold | 17.6 | 40 s | Pass | JT | None required |
Example entries only. The failure row is the one that matters: it shows the loop closing from reading to action to retest.
Why the action column is the whole point
Most monitoring sheets fail in the same place: a reading outside the target gets written down and nothing happens. A sheet without an action column lets that happen silently, because the row looks complete. With the column there, a failed reading forces a decision on the spot: investigate, escalate to the responsible person, and record what was found and done. When a thermostatic mixing valve is the cause, TMV servicing is usually the fix; when the reading suggests something wider, what to do if legionella is detected sets out the escalation. If you are unsure whether a reading passes at all, the temperature checker answers in one step.
A monitoring sheet is a recording tool. A full sheet shows the checks happened and failures were acted on; it never certifies that a system is safe.
Free legionella risk assessment template
A structured Word document following the five-step approach in ACOP L8. Covers risk identification, written scheme, monitoring, and records. If it isn't written down, you can't evidence it.
Follows ACoP L8 and HSG274 Part 2. Free. No spam.
Paper sheet or the web log book
Paper works. Print the sheet monthly, clip it into the log book, fill it in at the outlet with the probe in your other hand. The weaknesses are the ones paper always has: no reminder that the round is due, no automatic check that every sentinel was visited, and a folder that can be lost.
The legionella log book on this site does the same job on screen: it names your outlets, prompts the round, stamps the date, and keeps the five years of history ACOP L8 expects without a filing cabinet. Many sites run both, the web log as the live record and a printed monthly sheet pinned by the calorifier. If you prefer a purely paper system, the log book template guide and the monitoring log sheet page cover the full paper set, including flushing and inspection logs alongside temperatures.
Mistakes that make the sheet worthless
- Copying last month's figures. Inspectors look for it, and identical readings month after month are the tell. A fabricated record is worse than a gap.
- No time-to-temperature. A hot outlet reaching 50°C after five minutes has failed the one-minute test even though the number looks right.
- Blended readings at mixer taps. Measure the hot and cold sides separately where you can; a mixed reading describes neither supply.
- Unnamed outlets. "Bathroom tap" fails when the building has six. Use the names from your sentinel outlet list.
- No initials. A reading nobody owns is a reading nobody took.
The template, like every recording tool on this site, is an indicative starting point that you adapt to the outlets and targets your risk assessment sets. What makes it valuable is not the sheet itself but the five years of completed, honest rows behind it.
Free legionella risk assessment template
A structured Word document following the five-step approach in ACOP L8. Covers risk identification, written scheme, monitoring, and records. If it isn't written down, you can't evidence it.
Follows ACoP L8 and HSG274 Part 2. Free. No spam.
Frequently asked questions
What should a legionella temperature monitoring sheet include?
A good sheet has one row per reading with columns for the date, the outlet or asset name, hot or cold, the temperature reached, the time it took to reach it, whether it passed, who took the reading, and any action taken. It also needs a header naming the site, the month, and the target figures: hot 50°C or more within one minute (55°C in healthcare), cold below 20°C within two minutes, calorifier flow at 60°C or above. Without the action column, a failed reading has nowhere to go.
How do you take a legionella temperature reading correctly?
Use a clean, calibrated probe thermometer. Run the outlet gently, place the probe in the flow, and watch the reading until it stabilises. On a hot outlet, note whether it reaches 50°C within one minute of opening; on a cold outlet, whether it drops below 20°C within two minutes. Record the stabilised figure, the time taken, and your initials. On mixer taps, take the hot and cold supplies separately where the arrangement allows, because a blended reading tells you nothing about either side.
How long should you keep legionella temperature records?
Keep them for at least five years, in line with ACOP L8. That applies whether the records are paper sheets in a folder or entries in a digital log. Five years of consistent monthly sheets is what demonstrates continuous control to an inspector or insurer, and it is also what lets you spot a slow drift, such as a calorifier gradually losing temperature, before it becomes a failure.
Is a paper temperature log acceptable for legionella?
Yes. ACOP L8 does not prescribe the format, only that monitoring is done, recorded and kept. A paper sheet in a log book is perfectly acceptable for a small premises, provided it is filled in at the time of the check, initialled, and stored where it can be produced. Digital logs add conveniences such as reminders and automatic date stamps, but the legal standard is the same: a real reading, recorded when it was taken.
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