Domestic Legionella Risk Assessments

Letting agents and landlords are obliged by law to carry out risk assessments for legionnaire’s disease, and if necessary, take action.

We’ve set out all the information you need to know below, which is taken from the HSE Code of Practice of Legionnaires Disease. We can provide Domestic Legionnaires Risk Assessments, and are Trustmark Approved for your peace of mind. Contact us here to arrange your Legionnaires Risk Assessments. We can also provide an up to date EPC for your property at the same time and assist you with any requirements for the Minimum Energy Efficiency Standards coming in 2018 at a reduced rate.

What is Legionnaires Disease?

Legionnaires is a pneumonia like illness caused by the Legionella bacteria, which can be fatal. Those most ‘at risk’ are the very young, the elderly and those with low immune systems such as cancer patients.

The bacteria are naturally occurring in water, and can multiply rapidly in warm stale water. Transmission is through aerosols (mist / fine water droplets / spray) which are inhaled. In a domestic household this can be by shower head, spa bath or taps.

The Law relating to Legionnaires Disease

The HSEs Approved Code of Practice (the “ACoP”) for the control of legionella bacteria has special status in law and therefore you or your managing agent can be prosecuted for breach of health and safety law if the Code is not followed, and cannot show compliance. Implementing the Code of Practice requires you to:

  • Identify and assess sources of risk;
  • Prepare a scheme (a written course of action) for preventing or controlling the risk;
  • Implement and manage the scheme – appointing a person to be managerially responsible – the “responsible person”;
  • Keep records and check what has been done, and is being done, is effective;
  • Review periodically, in case anything changes in your [water] system

Any landlord is instantly at a disadvantage here as, with the best will in the world, your own efforts to prevent or control risk can be undermined by the personal choices of someone living in your property. In addition, some monitoring procedures and tasks are not going to be possible for a landlord and the official guidance is devoid of alternative suggestions.

To assist you here, we have produced a brief Guide for Tenants which we issue to all properties where we have conducted a Legionnaires Risk Assessment.

So who is responsible for these Risk Assessments?

Where a property is under full management by a professional agent, then clearly the agent has responsibility for meeting these legal requirements. However, where the landlords is managing the property him or herself, then the landlords takes on that responsibility along with all the other legal requirements such as annual gas checks etc. As a managing agent you should cover yourself if your landlord does not want to have a Legionnaires Risk Assessment, as if you offer a full service, you are the ‘responsible person’ in the event of a problem. You should ask your Landlord to sign to say you have provided him advice on Legionnaires and that he/she is the ‘responsible person’.

Clearly, Houses in Multiple Occupation (HMOs) pose a greater risk here and the “responsible person” the person who has the duty to manage the property is obliged to carry out a risk assessment for this risk.

Although an individual house or flat generally poses no greater risk for legionella than an owner occupied property, unless there are unusual circumstances, nevertheless there is still a risk which must now be addressed by all landlords and agents.

The guidance specifies annual risk assessments and insists that landlords and agents keep records of these for at least five years.

Risk Factors – Design / Use

In theory, a domestic water system that is entirely mains fed, with hot water coming from a combination boiler (which provides hot water on demand with minimal storage) should be safer than a system incorporating a cold water storage tank and / or hot water cylinder. However, if the property is empty for a couple of weeks (holidays, between lettings or whatever) then there is the potential for water stagnation in the pipework. Systems with stored cold or hot water can be higher risk directly because of the condition of the equipment or design. A plastic tank is lower risk than an asbestos or galvanised tank, but a plastic tank full of scale and/or sediment is a high risk “asset”.

If there is low water turnover at the property eg a single person living in a house the risk can increase.

If you have any exotic equipment / facilities in your properties such as a spa pools, hot tubs or Jacuzzi’s then the tenant should be informed on exactly how to maintain this type of equipment in accordance with manufacturers’ instructions.

The Risk Assessment – Who and What to expect

Our legionella risk assessment includes:

  • A description of the system and all assets (tanks, cylinders etc) including photographs;
  • A condition survey and summary of risks;
  • A course of action to reduce or eliminate risks (which may include remedial works such as cleaning and disinfecting a water tank if it is contaminated or alterations to plumbing). The course of action will include periodic tasks that you should perform (and for landlords, guidance / advice to pass onto tenants)
  • A management structure detailing the responsible person[s]
  • Guidance for the tenant to reduce the risks

Risk Assessments – The Aftermath

Possession of a risk assessment does not necessarily imply you have a safe water system that is low risk. It is a snap-shot in time, and should be repeated at regular intervals. Properties where high risk issues have been identified should have the work completed as soon as possible. Failure to implement such work leaves the owner / operator open to prosecution if something should go wrong.

Once we’ve completed Risk Assessment, we highlight to our customer (either the landlord or the managing agent) any issues which need urgent action, and recommend where necessary a further assessment once the work has been completed.


The Code of Practice contains monitoring activities and tasks which may be necessary weekly, monthly, quarterly, 6 monthly and annually or as required. Some of these will be problematical for any landlord. We try and assist by providing our help sheet for the tenant to reduce the monitoring activities required.

Following on from that, if your property is empty for a couple of weeks between lettings and it has a cold water storage tank (and normally a hot water cylinder) you should be opening cold and hot taps served by the tank / cylinder combination and leave them running for several minutes. What you are doing is purging stagnant water from the stored water part of the system as well as purging stagnant water from pipework itself. At the same time turn on the kitchen cold tap and run that to purge stagnant water from the supply pipe.

If the system is all mains fed with no stored water (hot or cold) the same process applies. Purge the stagnant water.

Flushing / purging is one of the simplest and most effective ways to control legionella and for maximum effect do it just before the new tenants move in.

Risk Assessments – Reviews

Currently the requirements are to review the risk assessment ideally every 2 years, or if other circumstances arise such as change of use of the building or the water system or its use. The review is to consider if the risk assessment is still valid and whether the control measures are sufficient, effective or indeed being carried out.

The water system within an average house is hugely less complicated than that in a 40 roomed care home as is the range and complexity of the control measures. Change of use is unlikely but change of water system (or a partial change) is a possibility. For example, a badly executed bathroom conversion from say a bath / wash basin / wc combination to a “wet room” could create a water system where the risk of legionella proliferation could be increased as a result of bad plumbing.

If you decide to convert a house in your portfolio into several flats, then a new risk assessment is a requirement – change of use, change of water system and so.

f you decide to use us to carry out a 2 yearly review, we have the original report so we know where everything is, reducing time on site. So in some instances and especially with domestic properties we can reduce the price.


Guide to Legionnaires Disease