Legionella Testing FAQs
- craigtawc
- 4 days ago
- 3 min read
Managing Legionella risks involves more than just routine maintenance — it also requires understanding when and how to carry out Legionella testing. Below, we answer some of the most frequently asked questions to help you stay compliant, informed, and protected.
How often should Legionella testing be carried out?
The frequency of Legionella testing depends on several factors, including the type of water system, how it’s used, and the level of risk identified in your Legionella risk assessment.
As a general rule:
Low-risk systems should be tested annually.
High-risk environments — such as healthcare facilities, hotels, gyms, and leisure centres — may require testing quarterly or even more frequently.
The specific schedule for testing and monitoring should always be based on your written scheme of control, which is developed from your risk assessment. This ensures that the testing is appropriate to your system’s unique requirements and risk level.
What happens if Legionella is detected in the water system?
If Legionella bacteria are detected in your water system, it’s important to act quickly. Immediate remedial measures may include thermal or chemical disinfection, flushing outlets, conducting temperature control checks, or carrying out additional sampling to determine the extent of contamination.
In addition, you should review your Legionella risk assessment to identify the root cause of the issue and update your control measures accordingly. Detecting Legionella is a serious concern, but a swift and professional response can bring the situation back under control and minimise risk to users of the water system.
Can I use rapid Legionella tests instead of laboratory testing?
No, rapid Legionella tests should only be used as an early indication and must not replace laboratory-based sampling. These quick-result kits are not UKAS-accredited and therefore do not meet the standards required by the Health and Safety Executive (HSE).
Only laboratory results processed by a UKAS-accredited laboratory are legally recognised and can be used as evidence of compliance with HSE regulations. For accurate and defensible results, always use professional sampling services that work with accredited laboratories.
Who is responsible for Legionella testing?
The legal responsibility for Legionella testing lies with the duty holder. This is usually the employer, landlord, building owner, or person in control of the premises.
While the duty holder may appoint a competent Legionella testing company or specialist to carry out the sampling and reporting, the legal obligation to ensure testing is done correctly and on time remains with them. It’s vital that whoever is appointed is suitably trained and experienced in Legionella control procedures.
Do I still need a Legionella risk assessment if I carry out regular testing?
Yes, even if you conduct regular Legionella testing, you are still legally required to have a Legionella risk assessment in place.
Testing alone only provides a snapshot of whether Legionella is present in your water system at the time of sampling. It does not explain why bacteria may be growing or how to prevent future outbreaks. A risk assessment, on the other hand, is a comprehensive evaluation of your system that identifies areas of concern and defines how to control them.
Under HSE ACOP L8, an up-to-date Legionella risk assessment is mandatory for any business or premises where water is stored or used.
Where are Legionella samples taken from?
Legionella samples are taken from various locations within your water system, chosen based on risk factors and system design. Common sampling points include:
Taps and showers, especially those that are infrequently used.
Cold water storage tanks.
Hot water cylinders and calorifiers.
Cooling towers or evaporative condensers (if present).
Dead legs and outlets at risk of stagnation.
A trained Legionella testing professional will identify representative locations that best reflect the condition and performance of your system, ensuring that the sampling process is meaningful and effective.
Need Help with Legionella Testing?
At Absolute Water Compliance, we provide professional Legionella water sampling and testing services across the UK, working with UKAS-accredited laboratories to deliver reliable, HSE-compliant results. Whether you're in healthcare, hospitality, manufacturing, or office management, our expert team can help you monitor and manage your water systems safely.
📞 Call us today: 01226 491133
📧 Email: support@absolute-water.co.uk
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