How to Test for Legionella in Water

How to Test for Legionella in Water

Whether you’re an employer, or a facilities manager in control of a premises, it’s your responsibility to help prevent exposure to legionella, the bacteria that causes illnesses like legionnaires’ disease.

Testing your water and water systems is a complicated process that takes specialist expertise. It’s a big challenge all year round and, in the summer months, more difficult than ever as bacteria proliferates in warm conditions.

However, if your testing is carried out incorrectly, you could be leaving yourself exposed to fines and legal action – and your people exposed to a dangerous disease.

Read on to find out how we test for legionella in water and then go further to provide comprehensive support to help you meet your obligations.

1. Assess your water systems and risk levels

Guidelines from the Health & Safety Executive state that a thorough legionella risk assessment needs to be carried out by a ‘competent person who understands your water systems’. In the majority of cases, this will be an external team that specialises in water treatment and hygiene.

A legionella risk assessment will look at all of your systems including those that:

  • Have a water temperature between 20 and 45°c
  • Store or re-circulate water
  • May be contaminated from rust, organic matter, biofilms or iron oxide sludge
  • Release droplets of water (like showers)

The assessment will also pay special attention to systems used by people who are more susceptible to Legionnaires’ Disease. The HSE categorises these as:

  • People over 45 years of age
  • Smokers and heavy drinkers
  • People suffering from chronic respiratory or kidney disease
  • Anyone with an impaired immune system

At Comfort Services, our risk assessments are carried out in accordance with ACOP L8 & Guidance Document HSG274. With an effective risk assessment, you will understand all of the systems that are relevant, where your risk is greatest, and where harmful bacteria may be lurking.

2. Conduct accurate and precise water sampling

Once the relevant water systems have been identified, water samples need to be collected and analysed for the legionella bacteria. The HSE states that testing should be conducted in accordance with BS7592 in a UKAS-accredited laboratory.

At Comfort Services, we combine precision technology, a structured process for preserving sample integrity and fast results. Our quality sampling specialists work in accordance with BS 8552 – 2015, analysing samples and identifying contaminants like legionella in our own UKAS-accredited lab. In practice, that means you can get accurate results you can depend on and ensure no potential risk goes unnoticed.

3. Monitor and control risk on an ongoing basis

Crucially, testing for legionella in your water isn’t as simple as identifying the relevant systems and carrying out a single round of sample analysis. Working in-line with legislation, we recommend testing every two years or whenever there is a change in your system.

However, deciding on the right time for sampling is more nuanced. For example, in the warm weather, temperature control may be more difficult. As a result, you may need to significantly increase your testing to as often as once a month or even more.

This is the only way to keep track of the way that your risk levels will change, as well as new controls you may put into place.

This documentation can also become a useful way to demonstrate your processes for reducing legionella risk – an obligation if you have more than five employees.

After initial testing, we can draw on our extensive experience to advise on next actions, treatment, controls and safeguards you should put into place. We can also provide bespoke building hygiene log books, where your water management procedures can be documented for audit trails and you can plan preventative and testing works.

Finally, effective legionella control is a continual process. With Comfort Safety, you get a specialist team to become long-term partners for your water, your systems and the safety of your people.

Learn more about our Legionella Risk Assessments.

Visit legionella risk assessments compliance