Legionnaires’ disease could be on the rise in post-lockdown properties, according to a recent report by the Chartered Institute of Environmental Health (CIEH). HMM Features Editor Jack Wooler investigates why this is, and the actions required under law for landlords

As tenant activity increases and landlords begin moving residents into homes that have remained empty throughout lockdown, it is essential that water systems are not put back into use without considering the risks of Legionnaires’ disease.

In a report from the Chartered Institute of Environmental Health (CIEH), it has warned that as a result of the Coronavirus pandemic there is potential for an increase in susceptibility of Legionnaires’ disease.

The Legionnaires’ Disease: lockdown risks and reopening safely report advises that there are multiple reasons for an increased likelihood of the waterborne pathogens responsible for Legionella being present in the conditions that lockdown has created.

Such reasons include the fact that there will be more compromised respiratory systems during or after infection with the virus, and that (though housing has perhaps suffered less than other property types) the increase in empty buildings that Covid has produced provides the perfect breeding ground for Legionella.

With Legionella bacteria – the root of Legionnaires’ disease – being caused by water system stagnation, landlords should be more careful than ever with unoccupied premises.

Increased risk

Legionnaires’ disease is a type of pneumonia which can cause serious respiratory illness, caused by tiny droplets of water containing Legionella bacteria that are breathed into the lungs of susceptible people.

Legionella bacteria will inevitably enter man-made water systems, both hot and cold, and the degree of risk it poses will vary – but the results can be severe.

During the pandemic and the subsequent lockdown, the report states two main risk factors that may have increased within properties, creating ideal conditions for Legionella bacteria to grow in your water system – temperature, and time for stagnation to occur.

Legionella bacteria thrive at temperatures between 20°C and 50°C, so a key control measure for minimising the risk is to ensure that cold water is below 20°C and hot water is above 50°C. When water meets these requirements, Legionella bacteria will not grow.

However, water between those temperatures presents a greater degree of risk, particularly where it is left to stagnate. Generally, where water is left within a system without movement for more than a week the risk of growth will increase.

Legal requirements

As stated by The Legionella Control Association (LCA): “Simply reopening a building that has stood idle, without addressing the safety of its water system, is unacceptable and is likely to be in breach of the law.”

Under health and safety law, all landlords must manage the risks of exposure to Legionella bacteria. As such, owners and operators of water systems have a duty to keep them safe.

To ensure this safety, a scheme of control should be in place to address risk. Such a scheme will typically include checking water temperatures, programmed maintenance/checks, and flushing parts of the system that may contain stagnant water due to low use.

Where the risks within the water system change, the risk assessment must be reviewed and revised to address those changes.

The Health and Safety Executive (HSE) has advised that if the premises closed or had reduced occupancy during lockdown, the duty holder should review its risk assessment and manage the Legionella risks when they reinstate a water system or start using it again, or restart some types of air conditioning units.

Risk assessment

Ideally, changes in Legionella risk will have been considered at an early point in planning lockdown arrangements.

If not, it is vital to consider that risk now, particularly if it is foreseeable that buildings and water systems may remain shut down or subject to low usage for several weeks. Where conditions for Legionella bacteria growth exist, there is always an opportunity to put measures into place that reduce that risk.

For simple hot/cold water systems, a review could be straightforward, and duty holders can carry out the Legionella risk assessment if they are competent or they can use an independent contractor.

The main objectives should be to prevent stagnation and keep water temperatures outside of the 20-50°C range. If possible, it is advised to aim to ensure the turnover of any water stored in tanks every 24 hours and movement of water through pipework and outlets at least once a week to prevent it from becoming stagnant.

If this cannot be achieved because the building is closed, or there is significantly reduced use, landlords will need to take additional steps beyond their current control measures to ensure this can be achieved as far as possible. This may include flushing the entire water system (all outlets) weekly and, if possible, dropping the level of stored water in tanks.

If hot water systems are switched off to conserve energy, it is advised to ensure water stored in any associated tanks is also turned over within 24 hours.

Moving forwards

Covid has provided challenges for all in the sector, but it is vital that tenant safety is not put on the back-burner.

Legionella can and will develop in empty properties, and landlords have an obligation to ensure their tenants can enjoy safe, clean water.

By undertaking the measures provided by CIEH however, landlords can forget at least one of the worries of retaining empty stock.