Businesses, hotels and healthcare facilities have been urged to step up precautions against Legionella this summer, as higher temperatures increase the risk of the bacteria developing in water systems, the labour inspection department said on Wednesday.

The combination of heat and greater use of cooling systems can create conditions that allow the bacteria to grow if equipment is not properly maintained.

Legionella develops in artificial water systems where water remains stagnant, temperatures are unsuitable and maintenance is poor.

People become infected by inhaling tiny contaminated water droplets. The disease is not spread from person to person or by drinking water.

The department said particular care should be taken in hospitals, clinics, rehabilitation centres, elderly care homes, hotels and other tourist accommodation.

Large residential buildings, water storage tanks, spas, jacuzzis, cooling towers, central air conditioning systems and decorative fountains also require close monitoring.

The department said domestic split unit air conditioners are not usually a source of Legionella because they do not use stored water.

Employers and building managers are required to have a prevention and maintenance plan in place.

This includes appointing a person responsible for Legionella risk management and carrying out regular written risk assessments.

They should also ensure hot water remains above 50C and cold water below 25C where possible.

Taps and showers that are rarely used should be flushed regularly, while tanks, pipes, shower heads, filters and cooling towers should be cleaned and disinfected.

The department recommended regular maintenance of spas and hot tubs, laboratory testing as needed, and keeping records of inspections, cleaning, temperature checks, and water analyses.

Hospitals and care homes should implement stricter monitoring as patients and the elderly are more vulnerable to severe illness.

The department said that proper management of water systems is crucial for protecting workers and the public, reminding employers that preventing Legionella is part of their legal health and safety obligations.