Legionella Risk Assessment

What is legionella?

Legionella is the bacteria which causes legionnaire’s disease and is found naturally in environments such as lakes & rivers. When it enters a man-made water system (such as a hot & cold water system) the conditions and temperatures of this system can offer the opportunity for this bacteria to rapidly proliferate (grow). When this bacteria is turned into an aerosol or droplets (such as a shower) then it can cause potentially fatal illness to susceptible people who may be exposed. Risks and conditions which can cause people to exposed to legionella bacteria include

  • Temperature between 20c-45c
  • Dirt & Debris in the system(s) or other sources of nutrients
  • Areas of infrequent use or stagnation (eg. Dead legs)
  • Aerosol production (showers, spray outlets)


Legal requirements

 The Acop L8(4th edition) is the legislative document covering the control of legionella in the UK. This document is supported by the HSG274 guidance document.

Legionella risk assessments should be reviewed every 2 years (or if conditions change)  such as:

  • Changes to building use
  • Significant changes to the water system
  • Issue of new guidance

Legionella risk assessment

Our  fully qualified and experienced legionella risk assessor will attend at your property and explain in detail what is required to meet your legislative obligations. The assessor will need to meet with the building manager or responsible person and will need to inspect any previous legionella risk assessments that have been undertaken, and also any legionella monitoring log books. The legionella risk assessor will also check the competency of staff which will involve inspecting training records if you have any. Our Safetestassessor will discuss the types of people using the building such as ages of staff, regular visitors and building users in order to identify if susceptible people are present, and also to produce a risk rating for the legionella report

Once completed, then the assessor will need to inspect all of the water system(s) in full. This will involve inspection and testing of mains cold water supplies, cold water tanks, water heaters, water features, heating systems and all pipework feeding your taps, baths, sinks, showers and outlets. Temperatures will need to be tested from as many outlets as possible, photographs taken of general observations, and anything considered to be a risk. We issues that safetest regularly identify include dirt and debris In the system (sediment in cold water tanks, scaled taps/showers) infrequently used outlets and dead legs, temperatures out of range (temperatures between 20-45c favour growth of legionella bacteria and other issues that can contribute to the growth of legionella bacteria.

Our assessor will need access to as many areas of the building and system as possible, which will help with the schematic diagram we will produce for your system(s) as part of the report. Our reports are compliant with the requirements of the Acop L8, HSG274.Once our assessor has conducted the full site and personnel review, we will produce the legionella risk assessment report.

We can also assist with any remedial, cleaning & disinfection works that may be required.


Our Accreditations

Our Accreditations