Legionella Testing Services

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Legionella Sampling & Laboratory Analysis

Keeping your water system safe is a key responsibility for every facilities manager.

Routine sampling helps confirm whether your control measures are working. It also supports compliance with ACoP L8 and HSG274 guidance.

We take water samples from agreed outlets, tanks or plant. These are then sent to a UKAS accredited laboratory for analysis. You receive clear results, plain English interpretation and practical next steps.

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Whether you manage a commercial property, a healthcare facility or an industrial site, regular testing can form part of a safe and compliant water management programme.

Your Trusted Partner for Legionella Testing

If you are here, you may need samples taken as part of your compliance programme.

You may also need checks after a risk assessment, poor temperature results or a system change.

At Titan Water, we provide professional sampling and microbiological analysis for many types of water systems. This includes:

Hot and cold outlets
Cold water storage tanks
Calorifiers
Showers
Spa pools and other higher risk systems

Our engineers follow recognised sampling procedures. Samples are then sent to a UKAS accredited laboratory.

You receive clear results, useful notes and straightforward advice on what to do next.

Nationwide Service
Reliable Expertise Wherever You Are

Our management team works from Titan Water’s head office near Liverpool. From there, our engineers support clients across the North West and wider UK.

We carry out water sampling for hotels, healthcare sites, commercial buildings, leisure facilities and industrial systems.

If you need routine sampling, follow up checks or support after a positive result, we can help you plan the right next step.

Team Titan

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Your Questions Answered

What Is Legionella Sampling

Legionella sampling checks water for the presence of Legionella bacteria.

Samples are taken from selected parts of the system and sent to a laboratory for analysis.

This helps show whether your control measures are working. It can also highlight hidden problems that may not be obvious from temperature checks, flushing records or visual inspections.

Legionnaires’ disease can be serious and potentially fatal, especially for vulnerable people. That is why accurate sampling and clear follow up action matter.

Why Test for Legionella

Legionella bacteria can occur naturally in water. They can multiply in man made systems when water is warm, stagnant or poorly circulated.

If contaminated water becomes airborne in fine droplets, people may breathe it in. This can lead to Legionnaires’ disease.

Sampling helps identify developing problems before they become harder to control.

You may need to sample if:

Your building serves vulnerable users
There are complex or ageing water systems
There has been a significant change in how the system is used
Temperature or flushing checks fall outside acceptable ranges
Refurbishment or maintenance work may have affected water quality

Testing is often part of an ongoing programme of monitoring. For more on the wider control measures involved, see our dedicated page Water Hygiene Monitoring Services.

When Should Legionella Sampling Be Carried Out?

The right sampling frequency depends on your system, risk level and control measures.

Sampling may be needed:

In higher risk sites, such as hospitals, care homes and leisure facilities
For spa pools, cooling towers or complex water systems
After poor temperature results or failed control measures
After cleaning, disinfection or remedial works
Following a positive result
When your risk assessment recommends it

For many commercial buildings, sampling may be carried out every 6 to 12 months.

Higher risk sites may need checks more often.

Your Legionella risk assessment should guide the schedule.

How The Sampling Process Works

Water samples should be taken using the correct method. This helps avoid contamination and makes the results more reliable.

The two most common laboratory methods are culture analysis and PCR analysis.

Culture Testing

Culture analysis is the recognised method for compliance.

Samples are processed in a UKAS accredited laboratory. Any live Legionella bacteria present are allowed to grow on selective media.

Results are measured in colony forming units per litre.

This method takes longer, but it gives the type of evidence auditors and regulators usually expect.

PCR Testing

PCR analysis is a faster method.

It detects Legionella DNA and can give an early indication when time is critical.

However, PCR may detect both live and dead bacteria. For that reason, it is often used alongside culture analysis rather than as a direct replacement.

Other Screening Methods

There are also on site tests that help provide an early indication of potential issues. These do not replace laboratory analysis but can support investigation work and pinpoint areas that require further attention.

Where Samples Are Taken

A good sampling strategy is essential for meaningful results. Sampling points should reflect the areas of your system where risks are most likely to occur.

Common sampling locations include:

Hot and cold water outlets, particularly those furthest from the source
Showers and thermostatic mixing valves
Cold water storage tanks
Calorifiers and water heaters
Little used outlets or areas with low flow

During sampling, details such as temperature, location and time of collection are recorded to support a clear audit trail. You can do a deeper dive on this in our blog How to Test for Legionella Bacteria in Water | Titan Water

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What Happens After Legionella Samples Are Taken?

Once samples are collected, they are labelled and handled carefully.

They are then transported to a UKAS accredited laboratory for analysis.

Culture results usually take around 7 to 10 days, depending on the laboratory.

Your report should show:

Whether Legionella bacteria were detected
The level found, where applicable
What the result means
Recommended next steps

Understanding Your Legionella Test Results

Once analysis is complete, results will help determine whether your system is performing as expected.

No Detection

If Legionella is not detected, your controls are likely to be working.

You should continue routine checks, flushing and maintenance.

Low Levels Detected

A low result does not always mean a major failure. It should still trigger a review of temperatures, water movement and usage patterns.

Targeted cleaning, flushing or adjustments may be enough to bring the system back under control.

High Levels Detected

High results need prompt action. This may include restricting access to outlets, disinfecting parts of the system or arranging a targeted investigation.

The key is to stay calm, act quickly and keep clear records.

If bacteria are found, the next step is usually to review the parts of the system most likely to be contributing.

This may include:

Extra flushing
Temperature checks
Tank cleaning
Shower head cleaning
System disinfection
Further sampling
Remedial works

In some cases, corrective work is needed to remove the underlying cause.

Helpful reading:

If you are managing an investigation following a positive result or a system failure, you may find our Legionella Investigation page useful.

How Legionella Sampling Supports Long Term Control

Sampling works best when it forms part of a wider water safety plan. It should sit alongside temperature monitoring, flushing, maintenance and clear record keeping.

This gives duty holders better evidence that the system is being managed properly.

It also makes it easier to respond quickly if results change in future.

Speak to an Expert

If you need support with your legionella testing programme, or want to discuss findings from recent sample results, you can speak directly with our team. We can help you understand what level of sampling is appropriate for your system and how it fits into your wider water hygiene responsibilities.

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What Our Clients Say

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Frequently Asked Questions

How long does Legionella testing take from sample collection to results

Most culture results take around 7 to 10 days.

This is because the bacteria need time to grow in the laboratory.

Faster PCR options may be available when urgent early information is needed.

Do I need to test for Legionella if my temperature records are always within range

Possibly.

Good temperatures are important, but they do not always prove bacteria are absent.

Sampling gives extra assurance, especially in higher risk systems.

Can Legionella testing be carried out while the building is in full use

Yes.

Most sampling causes very little disruption.

Engineers usually need short access to plant rooms, outlets or tanks.

Is Legionella testing required by law

There is no blanket legal duty to sample every system at fixed intervals.

However, sampling may be needed based on your risk assessment, system type or control history.

How often should a commercial building consider Legionella testing

It depends on the risk profile of the system.

Some buildings sample every 6 to 12 months. Higher risk sites may need more frequent checks.

Is Legionella testing the same as water testing?

No.

This is a specific type of microbiological water analysis focused on Legionella bacteria.

Other water quality tests may also be useful depending on your system.

What happens if Legionella is detected

The next step depends on the level found.

You may need extra flushing, cleaning, disinfection, further sampling or remedial works.

Can I take Legionella samples myself or does it require a professional

It is better to use trained personnel.

Correct sampling helps prevent contamination and protects the chain of custody for the laboratory.

Are there signs that suggest my system might need Legionella testing

Consider sampling if there are poor temperatures, little used outlets, dirty tanks, recent system changes, odours, discoloured water or user complaints.

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