Legionella Testing vs Risk Assessment

Legionella Testing vs Risk Assessment: Which Do You Need?

Many building operators and landlords ask: “Do I just test the water?” or “Do I need a full risk assessment?” The truth is that both serve different purposes — and together, they form a complete water safety plan. In this article, we’ll explain the difference, when each is needed, and how they complement one another.

What is a Legionella Risk Assessment?

A Legionella risk assessment is a legal requirement under UK Health & Safety law (ACOP L8 and HSG274). It involves a site survey, review of the water system, identification of risks, and an action plan for control. The assessment must be carried out by a competent person and reviewed every two years or when system changes occur.

What is Legionella Testing?

Legionella testing is a sampling process that identifies whether the bacteria are present in water outlets or storage systems. It provides a snapshot of system health and verifies whether control measures, such as temperature control or disinfection, are effective. Testing is recommended at least every 6–12 months in most systems and more frequently in high-risk settings.

Key Differences

Risk assessments identify and mitigate risk sources, while testing confirms whether control measures are working. A test cannot replace a risk assessment but supports it by validating ongoing safety. Both are essential for CQC, HSE, and insurance compliance.

Why You Need Both

A risk assessment without testing lacks proof that control measures work. Testing without an assessment may show contamination but not the root cause. Using both gives full assurance of safety and compliance.

How HSRA Helps

HSRA provides nationwide Legionella risk assessments and 2-in-1 testing kits with UKAS-accredited lab analysis. Our reports include clear actions and recommendations to keep your water systems safe and compliant.