Legionella compliance: the end-to-end map

“Legionella compliance” means meeting the duty to control exposure to legionella under the Health and Safety at Work etc. Act 1974, following the Approved Code of Practice L8 and the technical guidance in HSG274 — and being able to prove it. It is not a status a regulator awards and it is not a certificate. It is a demonstrable state of affairs: if an inspector asked tomorrow how you manage legionella, could you show them?

The proof always takes the same shape, whatever the building. Six stages, each producing something written. Work through them in order; each stage below links the detailed guide and the tool or template that produces that stage’s output.

Compliance in one page

Stage 1: The duty (HSWA 1974)

The duty to control legionella sits with the duty holder: the employer, the self-employed person, or whoever has control of the premises. For a rented building that is usually the landlord for any communal or shared water system; for a workplace it is the employer. The duty cannot be delegated away. Hiring a water hygiene contractor does not transfer it — the duty holder remains answerable for whether the risk is being controlled.

Day to day, the duty holder appoints a responsible person to take managerial responsibility for the scheme, with enough authority and competence to do the job. The appointment is an internal one — there is no external register or licence — but it should be written down, because “who is your responsible person?” is one of the first questions an inspector asks. Duty holder, responsible person, competent person: who is who? separates the three roles, and the responsible person appointment letter shows the seven sections a written appointment should cover.

Stage 2: The risk assessment (ACOP L8)

L8 is the Approved Code of Practice for the control of legionella in water systems. It requires the duty holder to identify and assess the risk: a suitable and sufficient written assessment of the actual water system. Because L8 is approved, a court treats a failure to follow it as evidence of a breach of the underlying law unless you can show you controlled the risk just as effectively another way. In practice, following L8 is the recognised route to complying with the law.

“Suitable and sufficient” is the legal test, not a page count. The assessment has to identify the significant risks in your system — stored hot water, cold water tanks, dead legs, little-used outlets, TMVs, spray outlets — and support a proportionate control scheme. A copied generic document that never mentions your building fails that test even if it looks thorough. ACOP L8 explained covers what the code expects; the Risk Assessment Builder turns nine answers about your building into an indicative risk profile and monitoring schedule, and the free template gives the written structure. The Builder’s result is a starting point to structure a real assessment — it records, it never certifies.

Stage 3: The written scheme of control

The written scheme is what translates the assessment into day-to-day activity: the specific measures needed to prevent or control the risk, who carries each one out, how often, and what gets recorded. If the assessment says little-used outlets must be flushed weekly, the scheme names the outlets, the person, the day, and the log the flush is written in.

Two failure modes matter here. A scheme that is more elaborate than the risk requires collapses under its own weight within months. And an unimplemented scheme is worse than no scheme at all, because it creates a paper trail suggesting the duty is being discharged when it is not — exactly what an inspector’s questions are designed to expose. The written scheme of control guide sets out what the document must contain, and the written scheme template gives a structure to work from.

Stage 4: The controls (HSG274)

HSG274 is the technical guidance behind L8, published in three parts. Part 2 covers hot and cold water systems and is where the familiar numbers live: hot water at outlets reaching at least 50°C within one minute (55°C in healthcare), cold water below 20°C within two minutes, calorifiers storing at 60°C or above. Around those temperatures sit the routine tasks: weekly flushing of little-used outlets, cleaning and descaling shower heads and hoses, inspecting cold water storage tanks, and servicing TMVs — six-monthly in healthcare, typically annually elsewhere.

Your assessment sets which of these apply and at what frequency; HSG274 is the recognised starting point. The HSG274 guide explains all three parts, the monitoring schedule lays out the typical frequencies, and the temperature checker tests your readings against the thresholds.

Stage 5: The records

This is the stage compliance actually stands or falls on, because the records are the only part an inspector can see. The compliance file — paper or electronic — should hold the written assessment, an asset register and schematic of the water system, the written scheme, the monitoring logs, laboratory certificates for any samples, records of cleaning and maintenance, training records for the responsible person, and a record of remedial action after every adverse finding.

When an inspector visits, the first thing they ask for is the monitoring records, typically covering at least the last 12 months: temperature checks, flushing logs, inspections and any sampling results, alongside the risk assessment, the written scheme and the responsible person’s appointment. The first 12 months show the regime is running now; because ACOP L8 expects records kept for at least five years, the inspector can ask to go back further if something needs explaining. The log book tool lets you record checks as you do them and export or print the log, and what to expect in an HSE legionella inspection walks through the visit itself.

Stage 6: The review

The chain only holds while it reflects the building as it is now. Review the assessment regularly, and always when something changes: alterations to the water system or the building, a change of use or occupancy, new evidence about the risk, or an adverse finding such as a positive sample. A review that finds nothing to change is still worth recording — the dated review note is itself evidence the duty is being managed.

An assessment left unreviewed for years despite obvious changes is one of the most common findings in HSE investigations, because it tells the inspector every later stage has been running on stale assumptions. The risk assessment checklist is a practical way to run the review.

Where compliance breaks down

The failures that come up most often in HSE investigation reports and CQC findings are not exotic. They are usually some combination of:

• A risk assessment not reviewed for years, despite changes to the building or the water system
• A control scheme requiring monthly monitoring, with gaps in the log covering months at a time
• No record of remedial action after an adverse finding that should have triggered disinfection
• A responsible person who has left the organisation, with nobody formally appointed in their place
• Temperature readings the equipment on site could not physically produce — the classic signature of back-filled records
• No flushing records for the little-used outlets the assessment itself identified
• Assessments of generic, copied text that never identify the actual features of the specific building

Most of these are straightforward to fix once identified. The risk is not that the problems are hard; it is that they accumulate quietly while the duty holder believes the job is done.

When inspectors get involved

HSE becomes involved in two ways. Reactive investigation follows a case of Legionnaires’ disease linked to the premises or a complaint: the health protection team leads the epidemiological work and HSE investigates the duty holder’s compliance. Proactive inspection happens where a sector or building type has been identified as higher risk, or as part of a themed inspection programme, and can happen without notice. Either way, the inspection is above all a records inspection — who inspects, what triggers a visit, and what they ask for first.

For healthcare providers and care homes in England, the Care Quality Commission inspects routinely rather than after an incident, and looks at water safety under its “Safe” domain, expecting the L8 components plus the HTM 04-01 requirements. Missing records or an unimplemented scheme can pull down the rating on their own.

If the records are missing, inadequate, or do not match what is actually happening on site, the question becomes what happens next. Legionella enforcement action, stage by stage covers the pathway from advice through improvement and prohibition notices to Fee for Intervention and prosecution, and the Enforcement Tracker records real UK cases and fines.

An honest, well-kept file showing a system with issues being actively managed is better evidence than a perfect-looking file that was clearly filled in once a year. Inspectors are not looking for a “compliant” sticker; they are looking for a duty holder who understands the system, has a scheme that fits the risk, and is actually running it.