Please note if you are a provider registered with the Care Quality Commission (CQC), and with premises located in England, they are the relevant regulatory body for patient safety matters. You can find guidance on the Care Quality Commission website.
What is legionella?
Legionella bacteria is commonly found in water. The bacteria multiply where temperatures are between 20-45°C and nutrients are available. The bacteria are dormant below 20°C and do not survive above 60°C.
Legionnaires' disease is a potentially fatal type of pneumonia, contracted by inhaling airborne water droplets containing viable legionella bacteria. Such droplets can be created, for example by:
- hot and cold water outlets
- atomisers;
- wet air conditioning plant
- whirlpool or hydrotherapy baths
Anyone can develop Legionnaires' disease, but the elderly, smokers, alcoholics and those with cancer, diabetes or chronic respiratory or kidney disease are at more risk.
If you run a care home or healthcare premises, it is likely that you will have residents or patients that are at higher risk of contracting the disease. It can be contracted by breathing in tiny droplets of water, for example when using showers, taps or fine sprays etc.
HSE's Legionnaires' disease website provides information on managing the risks
Assessing the risk
Health and social care providers should carry out a full COSHH risk assessment of their hot and cold water systems, to:
- identify who is at risk
- ensure adequate measures are in place to control the risks
Using temperature control
Where temperature is used to control the risk, hot water should be stored above 60°C, hot water distribution should be above 50°C and cold water storage and distribution should be below 20°C. Infrequently used outlets should be flushed out regularly and showerheads de-scaled and cleaned.
The primary method used to control the risk from legionella is water temperature control.
Water services should be operated at temperatures that prevent legionella growth:
- hot water storage cylinders (calorifiers) should store water at 60°C or higher
- hot water should be distributed at 50°C or higher (thermostatic mixer valves need to be fitted as close as possible to outlets, where a scald risk is identified)
- cold water should be stored and distributed below 20°C
A competent person should routinely check, inspect and clean the system, in accordance with the risk assessment.
You must identify 'sentinel' outlets (furthest and closest to each tank or cylinder) for monthly checking of the distribution temperatures. You should also check the hot water storage cylinder temperatures every month and cold water tank temperatures at least every 6 months.
Keeping the system clean
To control the risk you will need to ensure that hot and cold water storage tanks, distribution pipe work and outlets remain clean.
Stagnant water favours legionella growth. To reduce the risk you should remove dead legs/dead ends in pipe-work, flush out infrequently used outlets (including showerheads and taps) at least weekly and clean and de-scale shower heads and hoses at least quarterly.
Cold-water storage tanks should be cleaned periodically and water should be drained from hot water cylinders to check for debris or signs of corrosion.
Design systems
Design systems to minimise legionella growth, by:
- keeping pipe work as short and direct as possible
- adequately insulating pipes and tanks
- using materials that do not encourage the growth of legionella
- preventing contamination, for example by fitting tanks with lids and insect screens
Additional controls
Water samples should be analysed for legionella periodically to demonstrate that bacteria counts are acceptable. The frequency should be determined by level of risk, in accordance with the risk assessment.
Other methods to control legionella include copper and silver ionisation and biocide treatments (such as chlorine dioxide). To ensure they remain effective, their application will need suitable assessment as part of the overall water treatment programme including proper installation, maintenance and monitoring.