Legionnaires’ disease is a potentially fatal form of pneumonia caused by breathing in water droplets containing Legionella bacteria. Anybody can fall ill with the disease, but particular groups are more vulnerable, including people with immunodeficiencies and individuals suffering from chronic respiratory conditions or lung, heart or kidney disease. 

Just as anyone is susceptible to Legionella infection, any water system can present a contamination risk. Legionella bacteria develop in water temperatures between 25-40°C and are most commonly found in purpose-built systems such as cooling towers, evaporative condensers, spa pools, storage tanks, taps, water features and wet or hybrid system air conditioning units. 

As a duty holder or employer, you’re required under health and safety law to take suitable precautions to prevent or control the risk of Legionella exposure. If you can’t assess your site’s hazards yourself, you must appoint a competent person to do it for you.  

According to current HSE guidance, your Legionella risk assessment should include: 

  • Management responsibilities, including the name of your competent person 
  • A description of your system and any potential risk sources
  • The controls you currently have in place to minimise hazards 
  • Your monitoring, inspection and maintenance procedures
  • Records of your monitoring results, inspection and checks 
  • The date of your next review 

Many businesses discount Legionnaires’ disease as a thing of the past, yet deaths linked to Legionella exposure have risen in recent years. The COVID-19 pandemic has also ramped up risks, with extended building closures allowing the build-up of harmful bacteria. It’s therefore more important than ever to develop a robust monitoring and maintenance programme.

Past prosecutions spiral into the millions 

Over the past decade, duty holders have been slapped with significant fines and prison sentences for falling down on Legionella compliance requirements. Penalties have exceeded the £1 million mark and executives have been held personally responsible for safety breaches.  

  • In 2013, a Harlow-based cash management company was fined £1.8 million and £34,000 in costs for failing to eradicate Legionella risks from its water systems. After an employee contracted Legionnaires’ disease, an investigation revealed a series of compliance errors, including inadequate training, out-of-date policies and insufficient risk assessments. The firm has since ‘fundamentally overhauled the approach to managing water systems’.
  • In 2019, a care home company was fined £150,000 after a resident died of Legionnaires disease. A 56-year-old man was found to have been exposed to ‘vast quantities’ of Legionella bacteria growing within his room’s taps and shower.  The care home operator accepted responsibility for the incident but noted they had been poorly advised by external contractors.
  • In the same year, two business directors were handed 12-week prison sentences, suspended for 12 months, and £12,115 fines for ignoring warnings from water treatment consultants about onsite Legionella risks. An HSE investigation found the company had no Legionella risk assessments in place, was operating a cooling tower without biocide and had placed employees and the public at risk of Legionellosis exposure. 

Expert support to reduce Legionella hazards

Southalls has been helping businesses meet their Legionella compliance requirements for decades. As part of a complete risk assessment, an experienced health and safety specialist will locate possible sources of bacterial growth and recommend a step-by-step control plan, compliant with the L8 approved code of practice

A Southalls Legionella risk assessment evaluates:

  • Water temperature – Does it reach 20-45°C in any part of your water system?
  • Storage – Is water stored and/or re-circulated?
  • Conditions – Are nutrients present to feed the bacteria?
  • Risk groups – Are any employees, visitors or residents at greater risk due to age, lifestyle or health issues?

Your tailored action plan will first aim to eliminate Legionella bacteria through equipment or process improvement. If this isn’t possible, you’ll receive practical control measures – such as insulation, temperature testing, cleaning programmes or UV filters – that actively cut contamination levels. 

Your post-assessment report will also advise how to track progress and maintain audit-ready records that cover: 

  • The significant findings of your Legionella risk assessment
  • Written details of your controls and monitoring regime 
  • Results of your monitoring programme and additional follow-up actions