How to Check If Your Water Heater Temperature Is Safe for a Baby

Scalds are the most common burn injury in children under five. The American Burn Association reports that tap water burns account for a significant portion of those injuries — and most of them are preventable. One setting change on your water heater can dramatically reduce your child's risk.

5 sec — Time for a full-thickness burn at 140 degrees Fahrenheit tap water

The Number You Need to Know

The AAP recommends your home's hot water reach no higher than 120 degrees Fahrenheit at the tap. That's the threshold below which a serious scald requires prolonged exposure — giving you time to react. Above 130 degrees, a full-thickness burn can happen in under 30 seconds. At 140 degrees, it takes less than five seconds.

Most water heaters ship from the factory set to 140 degrees. Yours probably is, too — unless someone already changed it.

Why You Test at the Farthest Faucet

Don't test temperature at the tap closest to your water heater. Test at the farthest one. That's usually a bathroom sink or tub on the opposite end of the house from your utility closet.

Water cools slightly as it travels through your pipes. If the farthest faucet reads 120 degrees, you're within the safe range throughout your home. If you test close to the heater and get 118 degrees, you might still have 125-degree water coming out of the tub where you're bathing your baby.

1. Find your farthest faucet: Identify the hot-water tap farthest from your water heater — usually a bathroom sink or tub at the opposite end of the house.
2. Run the hot water for two minutes: Let the tap run fully hot for two full minutes to flush cold water from the pipes and get an accurate heater reading.
3. Measure with a thermometer: Hold a meat or cooking thermometer under the stream. Wait for the reading to stabilize, then write it down.
4. Adjust the thermostat if needed: If the reading exceeds 120 degrees Fahrenheit, locate the thermostat dial on your heater and set it to 120 degrees Fahrenheit. Turn off power first on electric units.
5. Retest after four hours: Wait four hours for the heater to reach its new temperature, then repeat the faucet test to confirm you're within the safe range.

How to Actually Do the Test

You need a cooking thermometer — a meat thermometer works fine. Run the hot water at your farthest faucet for two full minutes before testing. This clears the cold water sitting in the pipes and gives you a true read of what the heater is delivering.

Hold the thermometer under the stream and wait for the reading to stabilize. Write it down.

When my younger daughter was about eight months old, I did this test for the first time and got 133 degrees out of our hall bathroom faucet. I had assumed someone had already adjusted our heater when we moved in. They hadn't.

How to Adjust Your Water Heater

On most tank-style heaters, the thermostat dial is behind a panel near the bottom of the unit. Turn off power to the heater first if it's electric. Gas heaters usually have an external dial marked with temperature ranges or settings like "Hot," "A," "B," and "C" — which are not standardized and vary by manufacturer. If yours uses letters, consult the manual or look up your model online to find the degree equivalent.

Set it to 120 degrees, wait four hours, then retest at the farthest faucet.

One Step, Real Protection

This is a five-minute fix with meaningful consequences. According to the American Burn Association, lowering water heater temperature is one of the most effective single interventions for preventing childhood scald injuries at home.

Check the setting before your baby is mobile. And if you're not sure when you last checked — check today.