What temperature should you set your water heater to?

The right setting balances burn prevention, hot water needs and water hygiene.

The answer in 2 lines. For many US households, 120°F is a practical starting point for a residential water heater. It reduces scald risk and energy use, but it does not eliminate burns or guarantee control of Legionella bacteria. Higher storage temperatures may be appropriate for some households, with professional advice and thermostatic mixing valves to reduce burns. Measure the water at the faucet rather than trusting the dial alone. Shared building systems, medical risks and local requirements need individual consideration.

The first 3 steps

Identify your system and read its operating instructions. Use an accessible user control only as directed. Leave adjustments behind electrical access panels to a qualified professional.
Check hot water with a suitable kitchen thermometer, keeping your hands out of the stream. The CPSC tap-water scald guide explains checking temperature at the faucet and adjusting according to the appliance instructions.
Consider who lives in the home before changing the setting. Children, older adults and people at increased risk of Legionella infection may need a coordinated plan for storage temperature and scald protection.

Stop: danger

Scalding water: stop using the affected shower or tub until the temperature problem is addressed. Never leave a child unattended in the bath.
Electrical access panels: do not remove them to experiment with thermostat settings. A visible control and a thermostat behind a wired cover are different situations.
Water hotter than the setting suggests: do not assume another turn of the dial will solve it. Have the heater and any mixing valve checked.

Understand the temperature recommendations

Reference point	What it means
120°F	A federal consumer safety recommendation to reduce most tap-water scald injuries, not a guarantee against burns.
130°F–140°F	A range discussed in federal home water-hygiene guidance for killing germs such as Legionella, with increased burn risk.
Water delivered at the faucet	Must be considered separately from tank storage temperature, especially where mixing valves are installed.

The Department of Energy's residential water-heater guidance recommends 120°F for most residential applications; consult its usage advice for the household baseline. The CDC home water-hygiene guide, published in 2024 explains the higher-temperature option and its burn precautions. These are recommendations for different risks, not a single nationwide legal temperature limit.

What not to do

Turning the heater to maximum because the household runs out of hot water. Have capacity, settings and equipment condition assessed.
Assuming 120°F water cannot burn. Prolonged exposure can still cause serious injury.
Raising storage temperature without considering protection at showers and faucets.
Changing a shared building's water heater or a combination heating system without authorization and appropriate advice.

When a higher setting needs a coordinated plan

Ask your healthcare provider about your household's risk of Legionella illness before choosing a higher setting for that purpose. Older adults, smokers and people with certain lung conditions or weakened immune systems can be more vulnerable. The concern includes breathing contaminated water droplets, such as those produced by a shower.

If the heater is set above 120°F, the linked CDC guide advises thermostatic valves that mix hot and cold water at the tap to prevent burns. Ask a qualified plumber to assess appropriate protection and verify delivered temperatures. Do not assume the existing shower handle provides the necessary protection.

Explain your goal clearly: safe water at the fixtures, adequate hot water and a suitable approach to bacterial risk. A hotter tank alone is not a complete water-hygiene plan.

Renters, shared systems and unused fixtures

If you rent, send your landlord or building manager the measured temperature and identify the affected fixtures. Request an assessment rather than changing shared equipment. Local housing and plumbing rules may affect the required response; the household recommendations above are not a substitute for those rules.

After a faucet or shower has been unused for a while, follow the flushing section of the CDC home guide: run cold water fully for two minutes, then run hot water until it starts to feel hot. Avoid scalding exposure. Follow any additional instructions issued for your building or a water-service disruption.

Good to know

A thermostat marking is not a verified faucet temperature. Check the actual water after an adjustment once the heater has recovered, following its instructions.
Some electric tank heaters have separate thermostats. Have a professional make coordinated adjustments rather than opening the covers yourself.
Maintain the heater and clean fixtures according to their instructions. Temperature control does not replace maintenance.

Illustrative example: a grandparent finds the bathroom water uncomfortably hot. She measures it with a thermometer and asks a plumber to check the heater and shower protection. Because someone in the household has a weakened immune system, she also asks their healthcare provider about bacterial risk before deciding on a lower storage temperature.

A made-up story, for illustration.

Bobby

Sources, verification, confidence

Verified on November 4, 2026, for the United States. Confidence: high for the cited federal scald-prevention and home water-hygiene recommendations; medium for selecting a setting for an individual household. The CDC home guide was published in 2024; temperature values are guidance, not annual statistics or universal legal limits.