Landlords are being warned about the risks of Legionnaires’ disease after the UK recorded its hottest bank holiday weekend on record.

The disease thrives in water temperatures between 20 and 45 degrees Celsius, with 472 cases recorded in the UK in 2024 – the latest available data.

Legionella bacteria multiplies in warm water and can spread through tiny airborne water droplets. 

If inhaled, it can cause Legionnaires’ disease, a serious type of pneumonia that is particularly dangerous for older people and those with weaker immune systems.

Water stored in tanks or pipes, particularly if they are exposed to sunlight, can easily reach the ideal incubation temperature. 

During warmer periods, increased use of air-conditioning units can aerosolise the bacteria, allowing it to be inhaled.

A spokesperson for Legionella Guard warns: “With enforcement tightening under the Renters Rights Act, and temperatures rising as summer approaches, landlords cannot afford to treat Legionella risk as a tick‑box exercise.”

Typical symptoms of Legionnaires’ disease include chest pain, coughing, a high temperature, and breathlessness. 

While most people make a full recovery, legionellosis can be a serious condition.