Sampling shows whether your controls are working. Samples are taken to recognised standards and analysed by a UKAS-accredited laboratory, and we explain the results in plain English.
- UKAS-accredited laboratory analysis
- Sampling to BS 7592 and the guidance in HSG274, supporting ACoP L8
- A written report with the next steps spelled out
- Covering Leeds and West Yorkshire
What is Legionella sampling?
Legionella sampling means taking water samples from chosen points in a building and sending them to a UKAS-accredited laboratory to be tested. It gives you documented evidence of whether your control measures are working, and can show problems that temperature checks and inspections miss.
Legionnaires' disease can be fatal, especially for vulnerable people, which is why accurate sampling and a clear response to the results matter.
Who needs Legionella testing?
Any organisation that operates a water system may need testing as part of its Legionella control programme. It is most relevant for:
- Hospitals, care homes and hotels, where vulnerable people are present
- Schools, leisure centres and public buildings
- Offices, multi-occupancy and managed premises
- Landlords and housing providers with complex water systems
Not sure whether you need it? A Legionella risk assessment is the best starting point. It says whether sampling is needed and how often.
When should sampling be carried out?
There is no single frequency. It depends on the system, the risk and your control measures, and your risk assessment should set it. Sampling is more likely to be needed, and more often, if:
- The site is higher risk, such as a hospital, care home or leisure facility
- You have complex systems
- Temperature or flushing checks have failed
- Cleaning, disinfection or remedial works have just been done
- A previous result was positive
- The building is used differently, or has been empty and is being recommissioned
How does the sampling process work?
A sample taken the wrong way gives a result you cannot rely on. Our engineers follow a set method, record the temperature, location and time at each point, and send the samples to the laboratory in suitable conditions. The two main laboratory methods are:
Culture analysis
This is the method regulators and auditors expect for compliance. Any live Legionella present is grown in the laboratory and counted in colony forming units per litre. It takes longer, but gives the strongest evidence.
PCR analysis
PCR detects Legionella DNA and can give an early indication when time is critical. It can detect dead as well as live bacteria, so it is normally used alongside culture and not instead of it.
You receive a written report with the findings and recommended next steps.
Where are samples taken?
- Hot and cold outlets, particularly those furthest from the source
- Showers and thermostatic mixing valves
- Cold water storage tanks
- Calorifiers and water heaters
- Little-used outlets and areas of low flow
Understanding your results
No Legionella detected
Your controls are probably working. Carry on with routine monitoring, flushing and maintenance.
Low levels detected
This does not always mean a major failure, but it should trigger a review of temperatures, water movement and use. Cleaning, flushing or small adjustments often bring the system back under control.
High levels detected
This needs prompt action, which may include restricting outlets, disinfecting part of the system and investigating the cause. We will tell you straight away and agree the next step. Remedial works and tank cleaning, where needed, are handled by our own teams.
Frequently asked questions
Is sampling a legal requirement?
Not for every building. It is carried out where your risk assessment calls for it.
Is the laboratory accredited?
Samples are analysed by a UKAS-accredited laboratory, and details are available on request.
What if a sample is positive?
Stay calm, act quickly and keep records. We will review the system, advise on actions such as flushing, cleaning, disinfection or remedial works, and re-sample to confirm.
Request Legionella testing
To discuss a sampling programme, use the quote form.
Contact us for a Free Quote
Very happy with their very high standard of work Water Hygiene Services have been carrying out legionella risk assessments for us for a couple of years now. We have been very happy with their very high standard of work, their ability to work to tight deadlines and the general professional service they provide
