Legionella Testing & Water Quality Analysis
                     Legionella Testing & Water Quality Analysis
Legionella Control International is the UK’s leading legionella testing company offering a 
comprehensive suite of laboratory tests including UKAS-accredited legionella analysis, sampling 
and water tests to those with responsibility for the management of health and safety in the 
workplace.
We test water and other environmental samples for the presence of Legionella bacteria and 
other waterborne pathogens commonly found in engineered water systems and can tell you if 
your water meets current legal safety standards, and if not what you need to do about it.
UKAS accredited legionella testing solutions
Our confidential water quality analysis, interpretation and support services are cost effective, 
accurate and reliable. They have been developed to produce accurate test results that can be 
relied on, and support the control, compliance and environmental risk management activities of 
our clients throughout the UK and around the world.
The periodic sampling and testing of water sources for the presence of Legionella bacteria is a 
valuable means of demonstrating to the regulator, clients, colleagues and other important 
stakeholders that adequate control over a water system is being maintained and that levels of 
Legionella bacteria are kept within safe limits.
World-class water quality analysis specialists
We are a world-leading water safety and legionella risk management company offering a range 
of specialist services to help landlords, business owners, property and facilities managers, the 
duty holder and responsible person. We are expert in the delivery of pragmatic health and 
safety solutions that include the control of legionella and Legionnaires’ disease, legionella 
testing and analysis, the development and implementation of water safety control schemes, 
compliance auditing, City & Guilds training courses and software solutions to organisations 
throughout the United Kingdom and internationally.
Download our UKAS laboratory testing services brochure
If you would like to learn more about our legionella testing and water quality analysis services 
and how we can help you develop practical plans that keep people safe, protect your reputation 
and demonstrate to the regulator and other important stakeholders that you are taking 
reasonable steps to manage the legionellosis risks in your workplace then contact us today.
To speak with one of our legionella specialists’ call us today on 0330 223 36 86 or contact us 
here …
Our legionella testing solutions in more detail …
Our expert laboratory based UKAS legionella testing, water quality analysis and microbiology 
services operate to strict quality control and laboratory accreditation standards to ensure 
accuracy and reliability.
What is Legionnaires’ disease?
We are members of the UK’s Legionella Control Association (LCA) and are formally approved 
by them to deliver several specialist services including the testing and analysis of water 
samples for Legionella bacteria. Additionally, our management systems are certifiedby the 
British Standards Institution to ISO 9001 and ISO 14001, the international standards for quality 
and environmental management systems.
Jargon-free interpretation of test results
Many laboratory service providers simply present clients with the results of each test without 
any interpretation or support. However, we are leading experts in the control of Legionnaires’ 
disease, legionella bacteria and other water pathogens and have extensive experience in the 
analysis, interpretation and practical management and control of such risks. This means we can 
explain in jargon-free language what the results of individual tests mean for you, how your risk 
management activities may be affected, and help you develop a practical plan to resolve any 
problems that are identified in an effective and timely manner.
Regular sampling and testing of water for the presence of Legionella bacteria is a valuable 
means of demonstrating to the regulator and others that adequate control over a water system 
is being achieved to keep it safe.
Demonstrating adequate water system control
The periodic sampling and testing of water sources from man-made systems for the presence of 
the bacteria is a valuable means of demonstrating that adequate control over such a water 
system is being achieved. Put simply, if you don’t test your water how do you know it does 
contain unsafe levels of bacteria!
Additionally, the analysis of samples from water sources suspected of being contaminated with 
bacteria is also an important forensic tool that can be used to identify possible sources of risk 
within a water system.
Regular sampling and testing for legionella
The UK’s Health & Safety Executive (HSE) in their Approved Code of Practice ACOP L8 suggest the 
following:
“ … Periodic sampling and testing for the presence of legionella bacteria may also be relevant to 
show that adequate control is being achieved. However, reliably detecting the presence of 
legionella bacteria is technically difficult and requires specialist laboratory facilities.”
HSE “ACOP L8”.
The latest, fourth edition of the HSE’s ACOP L8 can be ordered direct from the HSE website if you 
require a hard copy, or downloaded here for free …
Download your copy of the HSE’s ACOP L8 here
How does Legionnaires disease testing work?
Qualified microbiological laboratories are experienced in the detection of legionella bacteria. 
Using specialist techniques, they can identify specific serogroups in individual samples which can 
help to forensically identify the source of an outbreak of Legionnaires’ disease.
How long does laboratory testing take?
UKAS accredited testing and analysis procedures for Legionella bacteria are typically performed 
using a standard culture procedure. This culture method usually takes between 10 and 12 days to 
complete. However, if analysis indicates a potential positive result for the presence of legionella 
bacteria during the testing phase, you will be notified immediately and the implications of the 
preliminary results explained in detail.
What’s the difference between legionella testing & sampling?
Many people think these refer to two separate methods of legionella testing. However, sampling 
merely refers to the process of taking the water sample – collecting it so it can later be tested 
under laboratory conditions.
When you use our legionella sampling service, you can rest assured we will undertake 
professional sample collections, in accordance with recognised British Standards. Furthermore, 
we will test those samples in a UKAS-accredited laboratory, ensuring you get reliable and 
accurate results each and every time.
Each water sample tested will receive a UKAS stamped test certificate which should be retained 
but can also be used to demonstrate to the regulator the effectiveness of your scheme of control.
Who can be appointed to monitor and test for legionella?
Anyone can take on this task, but they must have proper knowledge and understanding of the 
tasks to be completed. Training is typically advisable, to ensure there is a complete 
understanding of the steps required to keep the samples and water system free from 
contamination.
Learn more about legionella training
While you can do it yourself, providing you are competent to do so, in practice, many people 
decide to hire a competent expert to handle this aspect of testing and monitoring on their 
behalf.
Testing water for legionella
It is vital to follow the correct British Standard developed for use in these instances – BS7592. 
This standard applies to the sampling method developed to test and/or monitor legionella 
bacteria in water systems. If a biocide is used in the water treatment process, it should ideally be 
neutralised beforehand. All water samples collected should then be tested by a UKAS-accredited 
laboratory. All the samples our experts take when assessing a site for legionellosis risks are 
tested in this manner.
Download BS7592
How often should I test water for legionella?
Extensive guidance about when to test water for legionella is available in the HSE’s guidance 
document HSG274.
Cooling systems
Part 1 of the HSG274 guidance which deals with evaporative cooling systems including cooling 
towers calls for the make-up water and cooling water itself to be tested for both microbial 
activity and Legionella.
Download your copy of the HSE’s HSG274 Part 1 here
Dipslides are typically used to monitor microbial activity in the make-up water every three 
months, while the cooling water itself should be monitored on a weekly basis. In addition to this, 
the guidance requires the cooling water to be tested for legionella every three months at a 
minimum. If there are issues with the legionella test results from the cooling system, or there 
are changes evident that indicate a lack of control, more frequent testing may be prudent until 
good control is re-established.
Using dipslides to test for bacteria
Hot and cold water systems
Part 2 of HSG274, which deals with hot and cold water systems says that testing of mains fed 
domestic water systems is not usually required unless the risk assessment or on-going 
monitoring programme suggests there may be a problem.
Download your copy of the HSE’s HSG274 Part 2 here
Closed systems
If you have a closed water system that is not exposed to the atmosphere, ongoing monitoring 
would not typically be required. However, if there are ever any concerns or doubts over the 
cleanliness of the system, water temperatures, or other elements, more regular testing would 
again be a good idea.
The rule of thumb, therefore, is not to assume your system requires testing at specific intervals. 
Rather, you should meet the minimum requirements and take input from your system, a risk 
assessment, and resultant tests, to determine the most appropriate testing regimen.
How do I interpret legionella testing results?
This is perhaps the most complex part of the analysis process. It is one reason why many people 
decide to enlist the help of an experienced team of experts, who are trained to obtain and 
interpret test results for legionella in hot and cold water systems, cooling towers and other 
engineered water systems. By hiring an experienced team, you can be certain every aspect of 
your own water system will be covered, and that any potential risk of legionella can be 
identified, isolated, and treated, so it is not allowed to develop into a greater risk in the future.
The levels of bacteria present, the nature of the water system, and the risk assessment 
undertaken will all contribute to the appropriate steps that should be taken. The HSE’s technical 
guidance HSG274 contains further information and advice relating to interpretation of test 
results and which actions to take following those results.
The latest edition of the HSE’s HSG274 Part 2 can be ordered direct from the HSE website if you 
require a hard copy, or downloaded here…
Download your copy of the HSE’s HSG274 Part 2 here
Are there alternative methods of testing?
The current process involves sampling and testing cultures in UKAS-accredited laboratories. 
Typically, 10 to 12 days are required for cultures to be developed to attain a result. This may not 
be fast enough in situations where there is already a suspicion there could be elevated levels of 
legionella and other water-borne bacteria in the water system.
What about the qPCR test methods?
An alternative is to use the quantitative qPCR assay method, which reduces the testing time to 
just two days. This is recognised as a preferable route to take where there is a suspected 
outbreak of Legionnaires’ disease; where there may be doubt over the efficacy of current 
cleaning and disinfecting methods; and where this form of testing is used as a regular way of 
checking the situation on-site. In the latter case, proper use of the culture method should also 
be in place; however, the quicker qPCR test may prove useful in-between those testing 
regimens.
Learn more about the qPCR assay method of testing
It should be noted the qPCR samples should not completely replace the gold standard use of 
cultures to get results. They can, however, provide additional information and faster results in 
situations where speed is of the essence.
When faster qPCR testing does indicate the presence of elevated levels of legionella bacteria, 
appropriate steps can be taken to ensure the water system is treated, and that people at risk can 
be protected. But further in-depth testing via cultures should also be done to get more in-depth 
results over the longer period of time.
Need same day results? DIY test to get Yes-No results in 25 minutes
If time is of the essence and accurate results are required urgently, we also offer an innovative 
rapid DIY test, LegionellaFast which uses the latest “rapid-test” technology to detect Legionella 
bacteria in water.
Our handheld LegionellaFast is quick and simple to use and will deliver very accurate, easy to 
use, easy to understand YES::NO test results on-site in only 25 minutes.
Download our DIY test kit brochure here
Do you need water testing or a legionella risk assessment?
Domestic hot and cold water systems do not generally require testing for legionella unless there 
have been problems, the system is out of control or you suspect it may be associated with a case 
of Legionnaires’ disease. However, if you are the duty holder or responsible person, you do have 
a responsibility to confirm the water system is safe and not at risk of becoming home to 
dangerous levels of bacteria.
Every landlord and business in the UK that operates property, facilities or equipment and stores 
or uses water in any way will be required to conduct a legionella risk assessment – it is a legal 
requirement. While you can do this yourself, and test the water supply if required, wouldn’t it be 
easier to hire the experts to do it for you? This ensures you will be covered, and you will have 
the peace of mind of knowing your premises are safe, and that you have missed nothing.
Learn more about legionella risk assessments
Another point worth noting is that a water system that is open like a cooling tower or water 
feature, will likely be at greater risk of contamination than one that is closed. If the system is 
open, there is a greater chance of contaminated water droplets being spread through the air and 
being inhaled by people in the vicinity. By adopting a pro-active approach to legionella risk 
assessments and testing, you can make sure your business is protected, and that you are doing 
all you can to ensure no one is at risk of infection.
Relevant standards
The primary British Standards associated with the testing, detection, enumeration and sampling 
procedures include:
BS EN ISO 11731:2017
Water quality. Enumeration of Legionella
BS 7592:2008
Sampling for legionella bacteria in water systems. Code of practice
Additional laboratory services
Additionally, our microbiology laboratory facilities allow us to offer testing for a variety of other 
microbial organisms including:
Pseudomonas
Coliforms
E.coli
Enterococci
Clostridia
Moulds
Fungi
World-leading legionella testing company
We offer professional legionella testing and water quality analysis solutions to support 
businesses and those responsible for the safety of engineered water systems in the workplace. 
Our experienced legionella experts can help you manage your water facilities, meet your 
insurance obligations, and maintain compliance with the law and so keep people safe.
With offices in Manchester, London and Glasgow, supported by in-field consultants, engineers 
and technicians we can offer world-class environmental risk management and water testing 
solutions to businesses throughout the UK and internationally.
For more information about our water quality analysis services call us today on 0330 223 36 86 
or contact us here …