5 Common Mistakes in Legionella Risk Assessment Reports

A legionella risk assessment is only as good as the report that comes out of it. You can carry out a thorough on-site assessment, identify every risk condition, and understand the system inside out -- but if the report is poorly written, incomplete, or generic, it fails its purpose.

These are the five most common mistakes we see in legionella risk assessment reports, and how to avoid each one.

1. Generic boilerplate that is not site-specific

This is by far the most common problem. Reports that contain pages of copied-and-pasted text about legionella biology, regulatory background, and general guidance -- but only a few paragraphs of site-specific findings.

The duty holder does not need a textbook on legionella. They need to know what was found at their site, what the risks are, and what they need to do about it. Every paragraph in the report should relate to the specific premises being assessed.

How to fix it: Strip out generic content. If you need a background section, keep it to half a page. The bulk of the report should be findings, measurements, and recommendations specific to the site.

A good test: if you could swap the client's name and address and the report would still make sense, it is too generic.

2. Missing or incomplete temperature readings

Temperature monitoring is the foundation of legionella control, yet many reports either omit temperature readings entirely or include only partial data. If you assessed a building with 30 outlets but only recorded temperatures at four sentinel points, your report does not demonstrate a thorough assessment.

How to fix it: Record the temperature at every sentinel outlet you check. Note the run time before the reading was taken. If you could not access an outlet, record that fact. Include the readings in a table in the appendices and reference them in the findings.

3. Vague recommendations

"The water system should be maintained in good condition." This tells the duty holder nothing actionable. Recommendations like this are a common failing and they expose both the assessor and the duty holder to risk.

Good recommendations are specific, prioritised, and referenced to guidance:

• Bad: "Improve temperature control."
• Good: "Increase the calorifier thermostat setting from 55 degrees C to 60 degrees C to comply with HSG274 Part 2, paragraph 2.67. Priority: immediate."

How to fix it: For every recommendation, answer three questions: What exactly needs to be done? How urgently? What guidance does it relate to?

4. No photographs

A risk assessment report without photographs is significantly weaker than one with them. Photographs provide evidence of conditions found during the assessment, support your findings in the event of a dispute or enforcement action, and help the duty holder understand the issues.

Key items that should always be photographed:

• Cold water storage tanks (external condition and internal condition if accessible)
• Calorifiers and water heaters
• Any visible scale, corrosion, or biological growth
• Dead legs or redundant pipework
• TMV installations
• Inaccessible areas or restricted access points
• Plant room conditions
• Any defective components

How to fix it: Take photographs during every assessment. Include them in the report with captions that describe what is shown and where it was found. A photograph of a corroded tank lid tells the story far more effectively than a paragraph of text.

5. No clear risk ratings

Some reports list findings without clearly rating whether each condition is adequately controlled, needs improvement, or requires immediate action. Without a clear rating system, the duty holder cannot prioritise actions and the report lacks the structure that the HSE expects.

The ABC rating scale is widely used:

• A -- Adequately controlled. No action required beyond ongoing monitoring.
• B -- Improvements recommended. Remedial action should be planned.
• C -- Immediate action required. The duty holder must act without delay.

How to fix it: Rate every condition. Make the ratings prominent in the report -- ideally in a summary table near the front, as well as against each individual finding. If a condition was not assessed (for example, because of access restrictions), state that clearly.

The underlying issue

Most of these mistakes stem from the same root cause: assessors are under time pressure. Writing a thorough, site-specific report takes longer than copying a template, and commercial pressures often push assessors to produce reports quickly.

But a poor report is a liability -- for the assessor, for the duty holder, and for the people who use the building. If the HSE investigates after an outbreak, the report is the first document they will ask for. If it is generic, incomplete, or vague, it will not protect anyone.

L8Pro addresses these problems at the source. By guiding assessors through each condition on-site and capturing findings, temperatures, and photographs as you go, L8Pro generates a complete, site-specific PDF report automatically. No boilerplate, no missing data, no vague recommendations.