Legionella & Water Systems
Legionella bacteria live naturally in water and can grow in building plumbing, cooling towers, hot tubs and decorative fountains. Breathing in tiny droplets of contaminated water can cause Legionnaires' disease, a serious pneumonia.
- Plumbers
- HVAC
- Building Maintenance
How it spreads
- Legionella grows best in warm, stagnant water between about 77 and 113 degrees F, and in biofilm on pipes.
- People get sick by breathing mist or aerosols from showers, faucets, cooling towers, spas, fountains and pressure washing. It does not spread from person to person.
- Risk is higher for older adults, smokers and people with lung disease or weak immune systems. Workers can be exposed during water system work.
Work that creates risk
- Flushing, draining and cleaning water systems, cooling towers, hot tubs and decorative water features
- Pressure washing and misting equipment
- Restoring buildings after flooding. See Restoration Workers
- Renovating healthcare buildings. See Healthcare Construction
- Reopening buildings after long shutdowns, when water has sat unused
Prevention
- A water management program for large buildings: map the water system, set controls such as temperature and disinfectant levels, monitor and keep records
- Keep hot water at or above 140 degrees F at the heater where allowed and safe from scalds, and cold water below 77 degrees F; use mixing valves to prevent burns
- Flush rarely used taps and fixtures regularly; avoid dead ends in pipes
- Clean and disinfect cooling towers, spas and decorative features on schedule
- Keep filters and strainers clean; replace parts in good time
- After a shutdown, flush the system before reopening
Protecting yourself at work
- Avoid making aerosols when possible; use low-pressure methods.
- Wear a respirator (such as an N95 or a half-face with P100 filters) when work may create contaminated mist, and eye protection. See Respiratory Protection.
- Follow the site's water management plan and permits.
Symptoms
Cough, shortness of breath, fever, muscle aches and headache, appearing 2 to 14 days after exposure. Get medical care quickly and tell the doctor about your work. Report cases to your employer and the health department.
Standards & references
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