The safe water heater temperature recommended by the U.S. Consumer Product Safety Commission (CPSC) is 120 degrees Fahrenheit (49 degrees Celsius). Hotter water can cause serious burns in seconds, especially for young children and older adults. Check the temperature at a tap with a thermometer, and always test bath water by hand first.
This is general information, not medical advice. Talk to your doctor or pharmacist about your own situation.
CPSC urges everyone to lower their water heaters to 120°F. It says this setting may be needed to reduce or eliminate the risk of most tap water scald injuries, and that it also saves energy and money. The U.S. Department of Energy adds that some manufacturers set water heater thermostats at 140°F, while most households only need 120°F.
The difference of a few degrees matters more than most people expect. CPSC gives these burn times for hot tap water:
150°F: most adults suffer third-degree burns after 2 seconds.
140°F: burns occur after about 6 seconds.
130°F: burns occur after about 30 seconds.
120°F: even here, 5 minutes of exposure could cause third-degree burns.
So 120°F is not "burn proof." It gives a person minutes instead of seconds to get out of the water, which is why supervision and hand-testing still matter.
CPSC says most tap water scald injuries and deaths involve older adults and children under age five. NFPA adds people with disabilities to the high-risk group and notes that scald burns are the second leading cause of all burn injuries.
If you're helping an aging parent or have little ones at home, the water heater setting is one of the simplest safety checks you can make. It takes a thermometer, a few minutes and sometimes a call to the utility.
Thermostat dials are often inaccurate, according to the Department of Energy, so measure the water itself. Here's an example routine based on CPSC and Department of Energy tips:
Wait until no one has used hot water for at least two hours, or test first thing in the morning (CPSC).
Go to the tap farthest from the water heater (Department of Energy).
Run the hot water and hold a candy or meat thermometer under the faucet (CPSC).
Write down the reading. If it's above 120°F, adjust the thermostat and test again later.
Start with the manual. The Department of Energy says to check your owner's manual before making any change.
Gas water heaters: the dial is usually on the gas valve near the bottom of the tank (Department of Energy). Because thermostats differ, CPSC suggests calling your gas company for instructions.
Electric water heaters: shut off power at the circuit breaker or fuse first. Most have two thermostats behind upper and lower access panels, and CPSC says both must be set to the same temperature. CPSC notes some electric companies will adjust the thermostat for you at no charge.
Go in small steps. The Department of Energy suggests marking the starting setting, lowering it, waiting a couple of hours and measuring again. It may take a few rounds. Mark the final setting for next time.
Renters: if you live in an apartment, CPSC suggests talking with the building manager about lowering the tap water temperature.
If you aren't comfortable opening panels or working near gas valves, ask your utility or a qualified professional to do it.
Dishwashers: the Department of Energy notes that dishwashers without a booster heater may need water between 130°F and 140°F for best cleaning. Check your dishwasher's manual.
Bacteria: the Department of Energy says there is a very slight risk of Legionella bacteria growing when tanks are kept at 120°F, but it considers 120°F safe for most people.
Weakened immune system or chronic respiratory disease: the Department of Energy says these households may consider 140°F. Because that greatly raises scald risk, it suggests installing mixing valves or other temperature-regulating devices on taps used for washing and bathing. Ask your doctor what makes sense for you.
Install anti-scald devices on tub faucets and shower heads (NFPA).
Always supervise a child in or near a bathtub. CPSC warns that leaving a child alone in the bathroom even briefly could lead to serious injury.
Test bath water before a child gets in, or before you get in yourself. NFPA says water at the faucet should be less than 100°F (38°C) for a child's bath.
Move your hand, wrist and forearm through the water. It should feel warm, not hot (NFPA).
Our sister site's guide to bathroom safety for seniors covers other bathroom changes that pair well with a lower water temperature.
The NHS advises treating every burn or scald straight away:
Hold the burn under cool running water for 20 minutes, as soon as possible and within 3 hours.
Remove clothing or jewelry near the burn, but not anything stuck to the skin.
Once cooled, lay plastic wrap loosely over it rather than wrapping it around.
Don't put creams, oils or butter on the burn, and don't burst blisters.
Call 911 or go to the emergency room if the burn is very large or deep, or is on the face, genitals or bottom. The NHS also advises getting medical advice if you're not sure what to do, and especially for a child under 5.
CPSC recommends 120°F (49°C). The Department of Energy says most households only need 120°F.
For most homes, yes. CPSC says 140°F water can burn in about 6 seconds, and the Department of Energy calls it a scalding hazard. Some people with weakened immune systems may be advised otherwise, so ask your doctor.
NFPA says water at the faucet should be less than 100°F (38°C), and it should feel warm, not hot, on your hand, wrist and forearm.
CPSC says lowering the temperature conserves energy and saves money, and the Department of Energy says it also slows mineral buildup and corrosion.
RoomMend: Safer Home Plans is a free iPhone and iPad app, with an optional RoomMend Plus upgrade, that sets up a room-by-room safety checklist for your home or a parent's. You can log an issue like a too-hot water heater in about three taps with a timeframe, track the fix with notes until it's done, and get a reminder to look again after 30 days. It works offline with no account, ads or analytics, but it is not a home inspection or medical tool.
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