Landlord Legionella Risk Assessments

We are able to perform high quality landlord legionella risk assessments throughout Hampshire at competitive rates

Legionella Risk Assessments

Legionella is a naturally occurring bacteria which is found in low levels in domestic hot and cold water systems. Stagnant water between the temperatures of 20-50 degrees centigrade provide an ideal environment for the proliferation of legionella bacteria. The main issue associated with this is that if a person inhales water droplets containing high levels of legionella bacteria. If this happens it is possible that the person may contract Legionnaires Disease which is a fatal form of Pneumonia. DW Hampshire Ltd are able to assess domestic rental propeties and provide a comprehensive legionella risk assessment at competitive prices.

Legionella Risk Factors

Temperatures And Legionella Risk

Significant growth of legionella bacteria occurs in the range 35-40 degrees centigrade. At temperatures below 20 degrees centrigrade legionella bacteria remains dormant. At a temperature of 50 degrees centigrade the legionella bacteria start to die and at 60 degrees centigrade 90% of legionella bacteria are killed within two minutes. An essential part of performing a legionella risk assessment is to measure the hot and cold water temperatures at all outlets to make sure that the water is not at a temperature which provides an ideal environment for the legionella bacteria to proliferate.

setting a boiler temperature after a legionella risk assessment

Nutrients And Legionella Bacteria

Legionella bacteria require a source of food and this can be found in many forms within a domestic property. Biofilms are a slime type substance caused by water fouling and stagnation. Biofilms may be found in cold water storage tanks as a film on the surface of the water. If the cold water storage tank does not have a lid fouling by insects or dead animals such as mice, birds or squirrels falling into the tank and dying can provide a source of nutrients for legionella bacteria. Rust and limescale also provide a source of nutrients for legionella bacteria as well as impeding water flow and reducing heat transmission.

rusty water identified as providing nutrient in a legionella risk assessment

Water Stagnation And Legionella Proliferation

If water outlets such as taps, shower heads and hose reels are not used often legionella bacteria will multiply and may reach levels that are dangerous within as little as 10 days. Some examples of this may be a rental property that is vacant and has not been used for a few weeks alternatively if the tenants have been on holiday the water outlets will not have been used. If a tenant prefers to have a bath instead of a shower water may stagnate in the shower head and hose which will give rise to water droplets which can be inhaled when it is next used.

stagnant water in a garden hose reel identified in a legionella risk assessment.

Legionella Control Measures

There are a variety of simple control measures that can be adopted to control legionella bacteria and stop them reaching dangerous levels in a rental properties water system. Some simple measures may include setting the temperature controls on boilers and hot water tanks at the correct level or flushing water outlets that have been infrequently used . Once a legionella risk assessment has been conducted all of the control measures that are relevant to that property will be highlighted so that landlords and tenants are aware of the risks and how best to control them.

Legislation Relating To Legionella


Landlords have a legal duty of care to ensure that the risk of exposure to Legionella for tenants, residents and visitors to their property are adequately assessed and controlled.


The control of Legionella in rented property is a legal requirement, and duties of care are placed on Landlords as 'self-employed persons'. The House of Commons Briefing Paper 07307 (October 2015) states:


'Landlords of residential accommodation have a responsibility to take measures to ensure that their properties are free from health and safety hazards, this includes taking measures to combat Legionnaires' Disease.'


Other pieces of legislation which relate to landlords in respect of Legionella can be found in:


The Health and Safety at Work Act etc 1974


The Management of Health and Safety at Work Regulations 1999


The Control Of Substances Hazardous to Health Regulations 2002

Landlord Legionella Risk Assessment

The HSE Approved Code Of Practice L8 (Fourth Edition) 2013 sets out exactly what duty holders need to do to identify risks and control them We are able to assess rental properties and provide a detailed legionella risk assessment document with schematic diagram that will help landlords and letting agents meet their duty of care under the HSE ACOP L8.


Where the property allows adequate scope for inspection the legionella risk assessment will include:


Inspecting cold water storage tanks

Inspecting hot water storage tanks

Inspecting the property for dead legs in pipework

Testing water temperatures at taps, shower heads, flow pipes and cold water storage tanks.

Inspecting thermostats on boilers and hot water storage tanks for correct settings


We also provide advice leaflets to tenants to make them aware of the potential legionella risks in a domestic property and make them aware of the measures to take to minimise the risks.

More Information & Advice Leaflets

More information on legionella risk assessments and a useful fact sheet can be downloaded from the Elmhurst Energy website by clicking here.

Book your Legionella Risk Assessment today!

Simply call us on 01489 232250 to book your risk assessment and arrange a suitable date and time.


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