How to Turn Up (or Down) Your Water Heater Temperature
By Mike Holt, NJ Master Plumber · October 10, 2024 · 3 min read · Updated November 1, 2026
Quick answer
On a gas water heater, turn the temperature dial on the control valve toward the hotter mark in small steps. Tankless models change with the front panel. On an electric heater the thermostats sit behind covers, so call a plumber instead of opening them. 120°F is a common delivery target at the tap, not a universal storage setting. Scald protection and your manufacturer's instructions come first.
- Difficulty
- Simple on gas and tankless. Electric needs a professional
- Time
- 10 minutes, plus up to 3 hours to check
- You need
- Kitchen thermometer, your owner's manual
Rather not risk it? A licensed plumber can handle this for you, with written upfront flat-rate pricing options before any work starts.
Water that's too hot can scald. Water that's lukewarm runs out fast. A common target is about 120°F at the tap, but that's a delivery temperature, and the right tank setting depends on your equipment. Scald protection, the manufacturer's instructions and any required mixing valve govern what's safe. Here's what you can do on each kind of water heater.
How to turn up a gas water heater
Step 1: Find the control valve
It's the box at the bottom front of the tank where the gas line connects. It has two knobs: the gas control (On, Off, Pilot) and the temperature dial. You only need the temperature dial. Leave the gas control where it is.
Step 2: Turn the dial toward the hotter mark
Dials are marked from a low setting up to Hot or Very Hot, sometimes with letters in between. The direction varies by brand, so follow the markings. Move it one small step at a time, and check your manual for what each mark means.
Step 3: Wait, then check the water
Give the tank one to three hours to heat up, then test the water at a faucet (see below). If it's still not right, adjust again in another small step.
How to turn up an electric water heater
Call a plumber for this one. The thermostats on an electric heater sit behind metal covers, with 240-volt terminals right next to them, so we don't tell homeowners to open those covers. Most electric heaters have two thermostats, and they have to be set together. While you wait, you can check the water at the tap as described below, so you can tell us what you're getting.
How to change the temperature on a tankless water heater
Use the buttons on the front control panel or the remote panel on the wall. The change is close to instant. If the display shows an error code, look it up in the manual or call us. Tankless heaters work differently from tanks, which we explain in our overview of water heater types.
How to check the temperature at the tap
Run the hot water at the faucet closest to the water heater for two or three minutes, until it's as hot as it gets. Fill a glass, keeping your hands out of the stream, and put a kitchen thermometer in it. About 120°F is a common target at the tap.
Who needs extra scald protection?
Homes with young children or older adults should be especially careful. Their skin burns faster, and a burn at 140°F can happen in a few seconds. If you need hotter water in the tank, ask us about a mixing valve. It blends cold water into the hot so the faucets stay safer.
Still not hot enough?
If turning the heater up doesn't help, the cause is usually sediment in the tank, a failed electric element or thermostat, or a heater that's too small for your household. Call 908-873-6686. Our water heater repair and replacement page explains what we check, and our water heater cost guide covers what changes the price if it's time for a new one.
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Stop and call us if
- Turning it up doesn't make the water any hotter.
- You have an electric heater and want the temperature changed.
- You smell gas near the water heater. Leave immediately and call 911 and the gas utility from outdoors.
- The pilot light keeps going out, or the burner won't light.
- Water is leaking from the tank or from the valve on its side.
- The breaker for an electric water heater has tripped.
Call 908-873-6686.
Michael Holt
Owner and operator of Plumbing Doctor, NJ Master Plumber (Lic. #36BI01345600) and U.S. Marine Corps veteran.
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