Is legionella testing a legal requirement in London?

ACOP L8 requires that control measures are verified as effective. For most commercial and multi-occupancy buildings in London, regular water sampling is the standard way to demonstrate this. HSG274 recommends quarterly sampling for many building types.

How often should legionella testing be carried out in London?

Quarterly testing is recommended for most commercial and public buildings in London. Your risk assessment may specify a different frequency based on your building's risk profile. Post-remediation testing is required after any chlorination or decontamination work.

How much does legionella testing cost in London?

Costs depend on the number of sampling points at your London property. A small building with 3–5 sample points may start from around £200, while larger buildings with 10+ points are priced individually. We provide fixed-price quotes including sampling, lab fees, and reporting.

What happens if legionella is detected in the water samples?

If results exceed the action level of 100 CFU/litre, immediate remedial action is required — typically chlorination of the affected system. We'll advise on the appropriate response and can carry out remediation at your London premises. Re-sampling is required after treatment to confirm the system is safe.

How long do legionella test results take?

Laboratory results are typically available within 7–10 working days from sample collection. For urgent cases at London properties, we can request expedited processing at additional cost. We contact you immediately if any results exceed actionable levels.

What is the difference between a risk assessment and legionella testing?

A risk assessment is a physical survey that identifies hazards in your water system. Legionella testing is water sampling that confirms whether bacteria are actually present. Both are important — the risk assessment identifies what could go wrong, and testing confirms whether it has. Most London properties need both.

Legionella Testing in London

Professional legionella water sampling with UKAS-accredited laboratory analysis — fast results and clear reporting.

Get a Free Quote Learn More

Is Legionella Testing a Legal Requirement?

While ACOP L8 does not mandate routine testing for all buildings, it requires that control measures are verified as effective. For most commercial, healthcare, and multi-occupancy residential buildings, regular legionella water sampling is the accepted way to demonstrate this. HSG274 Part 2 recommends quarterly sampling for many building types.

The duty holder — typically the building owner, landlord, or facilities manager — is responsible for ensuring that the water system is monitored and that control measures are working. Regular testing provides the documentary evidence needed to demonstrate compliance.

Legionella testing involves taking water samples from your building's hot and cold water system and sending them to a UKAS-accredited laboratory for analysis. Testing confirms whether legionella bacteria are present and at what concentration — giving you the evidence you need to demonstrate compliance or trigger remedial action. Our engineers carry out sampling across London with results typically available within 7–10 working days.

What's Included

Sampling Strategy

Selection of representative and sentinel sampling points based on your system layout.

Aseptic Sample Collection

Water samples collected using sterile techniques to prevent cross-contamination.

UKAS Lab Analysis

All samples analysed by a UKAS-accredited laboratory to ISO 11731 standards.

Temperature Recording

Water temperatures recorded at each sampling point to correlate with results.

Results Interpretation

Expert interpretation of lab results with clear guidance on any actions required.

Compliance Documentation

Full sampling report for your records, supporting your ACOP L8 compliance programme.

Our Process

Get a Quote

Tell us about your building and we'll provide a fixed-price quote within 1 working day.

Sampling Visit Booked

We arrange a convenient date — sampling typically takes 1–2 hours on site.

On-Site Sampling

Our engineer collects water samples from agreed points using sterile techniques.

Lab Analysis

Samples are sent to a UKAS-accredited laboratory for legionella culture testing.

Results & Report

Results delivered within 7–10 working days with a clear written report.

Follow-Up Advice

If results are above actionable levels, we advise on next steps including remediation.

How Much Does Legionella Testing Cost?

Testing costs depend on the number of sampling points required, which is determined by your building's size and water system complexity. We provide fixed-price quotes that include sampling, laboratory analysis, and reporting. Contact us for a free estimate.

Get Your Free Quote

Common Issues We Find

•Elevated legionella counts indicating inadequate control measures
•Results above the action level of 100 CFU/litre requiring immediate remediation
•Inconsistent results suggesting intermittent contamination sources
•Failed post-chlorination verification samples requiring repeat treatment
•No baseline testing data making it impossible to track trends

Who Needs This

Regular legionella testing is recommended for all commercial buildings, healthcare facilities, care homes, hotels, schools, and multi-occupancy residential properties. It is essential for buildings where vulnerable people are present. Testing is also required after remedial works such as chlorination, to confirm the water system has been returned to safe levels.

Available Across London

Central London North London South London East London West London

Frequently Asked Questions

Ready to Book Your Legionella Testing in London?

Get a free, no-obligation quote from our London-based water hygiene team.

Get a Free Quote