Legionella FAQ

Legionella Frequently Asked Questions | Legionella Questions | Risk Assessment Support

When and how often do I need a legionella risk assessment?


The Approved Code of Practice L8 (HSG 274) in accordance with The Health & Safety at Work Act 1974 states that – “The Duty holder should arrange to review the assessment regularly and specifically when there is reason to suspect it is no longer valid. An indication of when to review the assessment and what to consider should be recorded and this may result from:

  • A change to the water system;
  • A change to the use of the building where the system is installed;
  • New information available about risks or control measures;
  • The results of checks indicating that control measures are no longer effective;
  • Changes to key personnel;
  • A case of legionnaires disease.”

Here at uRisk we recommend annual reviews to ensure correct implementation is being carried out. Legionella bacteria can double within 15 minutes, so it is important to review your risk assessment and monitoring records regularly.


Why do I need a legionella risk assessment?


HSG 274 Part 2 (Paragraph 2.122 – Pages 40-41)

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).

Frequency – There are no current guidelines on frequency of sampling other than actioning sampling.

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.

What to do if I get a Legionella positive sample?



• if the minority of samples are positive, the system should be resampled, if similar results are found again, a review of the control measures and risk assessment should be carried out to identify any remedial actions necessary or

• if the majority of samples are positive, the system may be colonised, albeit at a low level. An immediate review of the control measures and risk assessment should be carried out to identify any other remedial action required. Disinfection of the system should be considered.

>1000 cfu/l

The system should be resampled and an immediate review of the control measures and risk assessment carried out to identify any remedial actions, including possible disinfection of the system. Retesting should take place a few days after disinfection and at frequent intervals afterwards until a satisfactory level of control is achieved.

What monitoring must I do for Legionella?


‘Section 4: Water Logbook’ of this report identifies your site specific monitoring requirements.

However, for periodic maintenance and monitoring duties you must carry out, directly quoted from various HSE and other guidelines as specified, or as indicated by the risk assessment – “You must keep records of these actions in your logbook”.

HSG 274 Part 2 (Table 2.1: Checklist for hot and cold-water systems – Pages 31-33)

What are the Thermostatic Valve (TMV) temperature requirements?


HTM 04-01: Safe water in healthcare premises. Part A: Design, installation and commissioning practices (Table 2 – Page 55)

Areas where TMV type 3 valves should be fitted:

• Showers and hair-wash facilities (set to 41°C)

• Unassisted Baths (set to 41°C)

• Baths for Assisted Bathing (set to 46°C – to allow for the cold mass of the bath. NB – prior to patient immersion, water should be checked with a thermometer.)

• Bidets (set to 38°C)


When is a chlorination/disinfection required?


HSG 274 Part 2 (Paragraph 2.127 – Page 42)

Where necessary, hot and cold water services should be cleaned, flushed and disinfected in the following situations, as specified in BS 8558:

• on completion of a new water installation or refurbishment of a hot and cold water system;

• on installation of new components, especially those which have been pressure tested using water by the manufacturer (see the manufacturer’s instructions);

• where the hot and cold water is not used for a prolonged period and has not been flushed as recommended or the control measures have not been effective for a prolonged period. For example, this could be as little as two or three weeks, but will depend on the ambient temperature, condition of the water system, potential for exposure to aerosols and the susceptibility of users considered in a specific risk assessment;

• on routine inspection of the water storage tanks, where there is evidence of significant contamination or stagnation;

• if the system or part of it has been substantially altered or entered for maintenance purposes that may introduce contamination;

• following water sampling results that indicate evidence of microbial contamination of the water system (see Table 2.2 or 2.3);

• during, or following an outbreak or suspected outbreak of legionellosis linked to the system;

• or where indicated by the risk assessment.

How to comply with Legionella requirements?


As an employer, or a person in control of the premises, you are responsible for health and safety and need to take the right precautions to reduce the risks of exposure to legionella. You must understand how to:

• identify and assess sources of risk

• manage any risks

• prevent or control any risks

• keep and maintain the correct records and carry out any other duties you may have


Do we need training for Legionella?


“The responsible person(s) appointed to implement the control measures and strategies should be suitably informed, instructed, and trained and their suitability assessed.”

Section 18 – ACOP L8 HSG 274 Part 2 (Fourth Edition 2014)

What are the Water Supply (Water Fittings) Regulations 1999


These regulations are not directly concerned with legionella hazards, but govern the design, construction and use of materials in water systems. They cover:

• backflow protection (use of air gaps and non-return valves);

• the maintenance of water quality (tank designs);

• the use of materials (those that do not promote bacterial growth);

• water conservation (prevent leakage).

Must I improve access to water fittings?


ACOPs L8 states that “It is important that there should be ease of access to all parts of the system, components and associated equipment for management and maintenance purposes, e.g. tanks, calorifiers, thermostatic mixing valves (TMVs)…”

For more information please visit HSEs website for more information about ACOP L8.

Do I need to remove or replace Flexible Hoses?


You should ensure all flexible hoses comply with the WRAS approval scheme and be tested and comply with BS 6920. “In buildings where there are those with an increased susceptibility to infection or with processes requiring specific water characteristics, materials of an enhanced quality may be required.

Healthcare buildings and care homes should specifically take note of alerts and advice from the Department of Health and Health Facilities Scotland. For example, healthcare premises are advised against the use of ethylene propylene diene monomer (EPDM) lined flexible hoses (tails) as these have been shown to be a risk of microbial colonisation. Such flexible connections should therefore only be used in healthcare premises where an installation has to move during operation or is subject to vibration.”

HSE 274 Part 2 p.2.35

“Flexible hoses should be used only for the following applications: to allow for vibration of equipment; to accommodate vertical displacement of high and low baths and sinks; to facilitate essential maintenance and access of bespoke equipment when no alternative is available. Note – Where fitted, flexible hoses should be kept as short as possible and be kink-free as to no affect flow”. – The Health Technical Memorandum 04-01: Safe water in healthcare premises. Part A: Design, installation and commissioning states in p.3.41

Caution Hot Water Signs, Not Drinking Water, Drinking Water Signs


“The Regulations require employers to use a safety sign where there is a significant risk to health and safety” – The Health & Safety (Safety Signs and Signals) Regulations 1996 p.4

Caution signs are recommended at any location where there is the potential for scalding hot water. This includes where TMVs are located as they may fail.

Download the HSE Legionella Guidelines here for FREE


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Over 25 years of water hygiene and legionella control experience.

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

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When and how often do I need a risk assessment?

Under the Health and Safety at Work Act 1974 and in compliance with the Approved Code of Practice (ACoP L8, HSG 274), duty holders, including employers and those in control of premises, must ensure the health and safety of their employees or others who may be affected by their undertaking, this includes the risk of legionella. Legionnaires Disease is a form of pneumonia, which can be fatal and the main route of infection is through inhalation, by inhaling airborne water droplets that contain Legionella. This also applies if you are a private Landlord and have rental properties which are occupied.

This includes taking suitable precautions to prevent, manage and control the risk of exposure to legionella. You can do this by undertaking the following: a risk assessment, actioning all identified risks within the initial report with remedial works, sampling the water quality to confirm bacterial presence with water testing, and carrying out ongoing record keeping also known as monitoring.

Do I need testing, a risk assessment or both?

Legionella testing, water testing or sampling is not to be confused with a legionella risk assessment. You are required by law to undertake a legionella risk assessment under the Health and Safety at Work Act 1974, COSHH and a number of other regulations where you can show you are working to comply with the HSE's HSG 274 legionella guidelines.Testing or sampling whilst not a legal requirement on it's own, it plays an important role in determining how efficient a water system is managed. Your risk assessment may identify that sampling is required due to existing risks or as a control and management precaution. In this instance sampling then becomes a requirement from your assessment. Without an L8 risk assessment you will not know where and how many samples are required. And without water testing/sampling you cannot determine how affective your control and management is. These two actions therefore should be undertaken together, not necessarily at the same time but unison to effectively management your risk from legionella.

Water testing services include Legionella, e-Coli, total viable count (TVC), Pseudomonas, hard water, chlorine free, pH levels and more. Learn more about legionella testing. We only use UKAS approved laboratories giving you peace of mind that the test will be of the highest quality possible.

How much does an L8 risk assessment cost?

All assessments vary in prices depending on the number of water outlets, cold water storage tanks, hot water cylinders, combi boilers and other water assets that may be present. The number of assets within your water system will determine the time spent on site and how long it will take to produce your report.

So how much does it cost? Across the industry, prices vary enormously often depending on the size of the company you use and their processes, the speed of works and professionalism. There are two types of assessments, the first is commercial and the second domestic, also referred to as residential rental properties or landlord risk assessments.

Commercial risk assessments normally start from £250 to in excess of £750, however our prices start from £99 depending on the size of the water system and location.

Domestic risk assessments can range tremendously with a number of plumbers, gas engineers and other tradesmen offering these assessments without the specialist training, it’s important to check that your assessor or engineer is properly qualified. Our prices start from £55 for multiple landlord properties to £95 for single landlord properties. Our prices for residential rental properties are based on the property being no more than 5 bedrooms.

How long will the risk assessment take?

On average, the time our qualified assessor spends on site is 1 hour for every 10 outlets (sinks, showers, baths, etc). So an assessment can take anywhere between 30 minutes to 6 or 7 hours. It entirely depends on the size of your water system and the number of water assets you have such as cold water storage tanks, cylinders or combination boilers.

Our engineers will work closely with you to ensure minimal disruption to your business is caused. Clear and easy access to rooms and buildings will play a part in time spent on site at your premises.

When will I receive your findings?

You will receive your LRA report between 2-10 working days from the date the assessment was carried out. From time to time, not often, our team will need a little more time, so please expect to have your report no later than 30 days. Need your assessment sooner? Get your report, guaranteed next day delivery via email for just £50.

What happens after I receive the report?

Within your report document, you will have an action plan offering guidance which lists all identified risks, with photos, that need remedying in order of importance. By following our advice and undertaking remedial works you will reduce the risk of exposure to Legionnaires' disease.  Once all the remedial works are complete, you will then need to focus on implementing your monitoring (periodical checks and maintenance) with a logbook for recording keeping all legal duties and monitoring requirements.

Are uRisk qualified?

Yes, all of our assessors are fully qualified and accredited by City & Guilds and can help assist you in meeting compliance today for HSE (ACoP L8). We are also 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 our engineers are DBS Checked to ensure suitable people are entering your premises and to safeguard vulnerable people. We are committed to maintaining the highest standards.

Do uRisk service my area?

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

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
Brilliant company, customer service was great! And engineers were fantastic. Thanks again uRisk! Will definitely be using them for all future work.
Nikesh Gohil
Nikesh Gohil
12:49 12 Mar 18