Why temperature matters
CDC says Legionella grows best between 77°F and 113°F. That's why lukewarm water sitting in a heater or pipes is the problem zone.
Settings CDC points to
- Set the water heater at or above 120°F to minimize Legionella growth.
- 130–140°F kills many harmful germs but increases scalding risk. If you set it higher than 120°F, use thermostatic mixing valves at faucets and showers, and follow local scald rules.
- Flush the water heater on the schedule the manufacturer recommends.
After a trip or a long vacancy
Water that sits in pipes can lose its disinfectant and cool into the growth range. When you get back, run the hot and cold taps to bring fresh water through. That habit also helps with lead, since water that sits can pick up more lead.
Condo or apartment in Palos Heights? CDC notes that buildings with centralized hot water systems need a Legionella water management program, so check who maintains the water heater.
Quick questions
What temperature should my water heater be?
CDC guidance for property owners is to set the water heater at or above 120°F. 130–140°F kills many germs but raises scald risk, so use thermostatic mixing valves if you go higher, and follow local scald rules.
Sources
- Vacation Rental Owners and Managers (Legionella control) — CDC
- Monitoring Building Water — CDC
- National Primary Drinking Water Regulations — U.S. EPA
This guide is general information, not medical or legal advice. Palos Heights Water Filtration is an independent business and is not affiliated with the City of Palos Heights. Product certifications are model-specific and can change; check the current listing before you buy.
