Legionella Testing & Sampling

UKAS Accredited Laboratories Used

Legionella Testing, Analysis and Sampling


uRisk is a water hygiene specialist with nationwide coverage and over 25 years of experience. We provide legionella testing and a wide range of water testing with UKAS approved laboratories. All legionella sampling is carried out to the British Standards BS7592.

We work with all types of organisations from healthcare to commercial and industrial, as well as private dwellings. uRisk provides 2 types of legionella sampling services. These include engineer sampling by a qualified engineer who will undertake sampling to the required standards. Alternatively, we provide a legionella testing kit (DIY testing kit) that is cost-effective, non-intrusive and has a fast turnaround time. Before you consider legionella testing, you should first have a legionella risk assessment in place, as this is your legal requirement. This will help you to identify how many water systems you have and therefore how many samples you should take.

Important – Each sample bottle should be used at a single outlet (sink, shower, bath) only. Mixing samples from 2 or more locations may dilute your results and will be more costly to identify where the bacteria is present should you have a positive bacteria result.

Legionella Testing, Analysis, Sampling Services

Engineer Sampling

A qualified engineer will take legionella samples to British standards. From your legionella risk assessment they will identify the number of samples required and locations to take them from.

Legionella Testing Kit (DIY)

Receive your legionella testing kit (DIY) in the post. The package includes your sterile sample bottles, instructions, and a free pre-paid return package.  Perfect for a non-intrusive, cost effective legionella sampling.

Subscription Testing Kits

Order repeat periodic legionella testing sample bottles to be scheduled for delivery when you want them: quarterly, six monthly or annually. Order your legionella testing kit (DIY) subscription today.


What is Legionella Testing, Analysis, Sampling?


Legionella testing or analysis is the action of examining a water sample. This is where the laboratory will identify the presence or absence of legionella in the legionella sample collected, along with the bacterial count and legionella species. Legionella sampling is the action of sample collection and the strategy used to collect the sample. Therefore legionella testing/analysis and legionella sampling are two different stages in one process.

If you are ordering legionella testing without a suitable legionella risk assessment in place, the testing will not offer you any protection. In order to sample correctly, you must know where to take legionella samples from. For example, understanding your water system’s design and risk areas. If you are not sure what to do to meet your legal requirements. Contact us today for legionella guidance.

When and how often should I do a legionella test, analysis, sample?


In both hot and cold water systems, samples should be taken:

  • If considered necessary by the risk assessment;
  • from areas where the target control parameters are not met (i.e. where disinfectant levels are low or where temperatures are below 50°C (55°C in healthcare premises) for HWS or exceed 20°C for cold water systems);
  • from areas subject to low usage, stagnation, excess storage capacity, dead legs, excessive heat loss, cross flow from water system or other anomaly.


In cold water systems, samples should also be taken as required:

  • from the point of entry (or nearest outlet) if the water is supplied from a private water supply or where the temperature of the incoming mains supply is above 20°C from the cold water storage tank or tanks;
  • from the furthest and nearest outlet on each branch of the system (far and near sentinel outlets).


In hot water systems, samples should be taken as required:

  • from the calorifier hot water outlet and from the base of the calorifier, if it is safe to do so, as some systems are under considerable pressure;
  • from the furthest and nearest outlet on each branch of a single pipe system (far and near sentinel outlets);
  • from the furthest and nearest outlet on each loop of a circulating system (far and near sentinel outlets).


*There are no current guidelines on frequency of sampling other than actioning sampling per the ‘action to take’ . Routine sampling from sentinel points will aid water analysis and confirm monitoring is sufficient. Please refer to the HSG 274, HTMs, and manufacturers guidelines for sampling frequency.


Is legionella testing compulsory?


No, legionella testing is not compulsory. The HSE’s Approved Code of Practice (ACoP L8) HSG 274, states that you are currently legally required to undertake a legionella risk assessment, but not legionella testing/sampling.

However, whilst it is not compulsory, the HSG 274 confirms that the risk assessment may require or request that legionella samples are taken for a variety of reasons. For example, these might include high risks identified or the effectiveness of management and control.

Why carry out routine legionella sampling?


Routine legionella sampling is the most effective way to determine water quality. Without legionella testing, you are unable to identify water quality and therefore you are unable to determine whether your water management and legionella control is sufficient.

With periodic legionella testing, you are able to demonstrate that your water management and legionella control procedures are suitable and the water in your water system is fit for purpose.

All our water samples are tested in UKAS accredited laboratories as standard and we are able to carry out tests on a wide range of microbiological samples and chemical testing services.

Water Systems we Sample


  • Drinking Water (including water dispensers and coffee machines)
  • Hot and Cold Water Systems
  • Cold Water Storage Tanks
  • Hot Water Cylinders
  • Water Heaters
  • Dental Units
  • Swimming Pools
  • Spa Baths
  • Cooling Towers
  • Eye Showers
  • Eye Wash Units
  • Fountains and Features
  • Vending Machines
  • Closed Water Systems

View full range of Water Testing and Analysis

What is legionella sampling strategy?


Legionella sampling appears to be a simple process of filling a sterile sample bottle, but it can become extremely problematic as the method and process of sample taking can have an important effect on the final sample results. Let’s explore!

Pre-flush and post-flush – a pre-flush is a sample taken before the tap is flushed, and a post-flush is a sample taken after the tap is flushed for a period of time. Depending on how long the tap is run will determine how far into the water system the sample is taken from. This is why all sampling should be undertaken in accordance with BS 7592 as a simple change in how the sample is taken can have a significant impact on the results.

Mixing sample bottles – It is important not to mix samples from two outlets (taps, sinks, showers, baths, etc) into a single bottle. This will dilute any legionella positive results. It is also more costly should you have a legionella positive because you will need to take further legionella samples to identify where the legionella bacteria is present.

24 hour legionella testing – whilst this method will help provide a fast identification of legionella presence, it is not a UKAS approved method. Therefore results should be considered with caution.

Timing – legionella samples should be delivered to the UKAS laboratory within 24 hours of the sample being taken to ensure reliability of the results.

Appropriate techniques must be used to ensure the validity of the sample results. These techniques may include:


  • Appropriate use of PPE
  • Sampler cleanliness
  • Cross contamination

Legionella Sampling Bottles


Legionella sampling bottles are sterile bottles treated with sodium thiosulphate which aims to neutralise the effects of residual chlorine in the sample bottle. These UKAS approved bottles should also be collected in the appropriate containers. So you cannot use any old plastic bottle!

All samples should be labelled with the sample number, date, sample type, company name, sample location, sample system (hot or cold), water temperature. Chemical samples will also need to be taken using the appropriate bottles.

Legionella Sampling Competence


All water hygiene engineers are City and Guilds qualified and have been trained to take samples in a manner that is least likely to contaminate the sample. Sampling is undertaken to meet British standards BS7592.

Whilst it may appear to be obvious, there are many procedures to be followed during the sampling process. For instance, placing the bottle cap downwards can alter the sample results. It is very easy to create false and inaccurate results.


Do uRisk service my area?


Yes, uRisk’s services are nationwide. Whether you have one or multiple water systems and one or multiple sites, uRisk provide services to the nationwide, with engineers scattered throughout the UK, with offices based in Hertfordshire, a 30 minute train journey to London King’s Cross.

Head Office: uRisk, Units 11-12 Baldock Industrial Estate, London Road, Baldock, Hertfordshire, SG7 6NG.

Are uRisk qualified?


Yes, all of our Legionella Risk Assessors at uRisk are Legionella Risk Assessment qualified and accredited by City & Guilds and can help assist you in meeting compliance today for HSE (ACoP L8). uRisk is Safe Contractor and Construction Online approved so you can rest assured that you are working with a trusted water hygiene service provider who put health and safety first.

All uRisk engineers are DBS Checked to ensure suitable people are entering your premises and to safeguard vulnerable people.

Our booking process

Get a Quote

To get a quote you can phone, email or complete our ‘Get a Quote!’ form to receive a quotation within 24 hours.

Book an Appointment

Once you’re happy with your quote we’ll confirm a suitable date and estimated time of arrival for your appointment.

Your Appointment

An engineer will be with you on your scheduled date, and will call you prior to arrival (when safe and possible).

Report & Support

Our team will quality assess your report for PDF distribution, typically within 2-10 days of the site visit.

All payments are due prior to booking completion unless agreed in writing for 30 days from the date of invoice. We will hold your booking time for 24 hours whilst we wait for payment.

Why choose uRisk?

25 Years Experience

Over 25 years of water hygiene and legionella control experience.

Customer Service Excellence

Friendly and simple advice by phone, email & online at your convenience.

City & Guilds Qualified

All staff are trained water hygiene consultants and engineers.

Nationwide Coverage

With engineers located all across the UK, we’re never too far away.

UKAS Accredited Testing

Our labs are UKAS approved providing you with quality assurance.

Full Compliance Services

Your one stop shop for legionella control, no need to go elsewhere.

Contact Us

01462 419444

Head Office:

Baldock Herts SG7 6NG


Monday to Friday:

0900 - 1700

Offices Closed for Lunch:

1300 - 1400

Water Hygiene Services

Extremely happy with our legionella risk assessment carried out by uRisk, easy to understand and great customer service. Thanks again
Nickayla Robertson
Nickayla Robertson
21:22 15 Jan 19
Brilliant service! Thanks a lot for the hard graft
Leon Macauley
Leon Macauley
21:12 15 Jan 19
Brilliant Service, efficient, professional, punctual and friendly.
Alex Windsor
Alex Windsor
18:21 15 Jan 19
uRisk have been helping us with our Legionella Control for a number of years now. We've recently had a CQC audit and they were very impressed with our legionella compliance! Thank you for all your help.
Mike Port
Mike Port
20:41 07 Aug 18
Fantastic training courses and we've found the legionella risk assessment very easy to read and far more detailed than any we have previously had. 5 star service!
Gemma Pond
Gemma Pond
20:37 07 Aug 18
Incredibly detailed and professional team. Have been beyond helpful with with our CQC legionella compliance for our Safety. They’ve found solutions to fit around how we work and our budgets. We are always advised with reference to HSE which has been brilliant.
Amy Thorne
Amy Thorne
20:29 07 Aug 18
We're a small GP practice and started using uRisk for legionella risk assessments. We opted to use their remedial and monitoring services and they've been absolutely great. We cannot recommend them enough! Thank you so much!
Amanda Pates
Amanda Pates
18:30 07 Aug 18