How to Adjust Your Water Heater Temperature

Understanding Your Water Heater's Temperature Settings

Water heaters come with a thermostat that controls how hot the water gets before it leaves the tank. Most residential water heaters have a dial or digital display on the outside that shows the current temperature setting. The standard factory setting is typically between 120°F and 140°F, though many manufacturers default to 140°F. Understanding this setting is important because it affects both your comfort and your utility bills.

The temperature you choose determines how much energy your water heater uses. Higher temperatures mean the heating element or burner runs more often to maintain that heat level. According to the U.S. Department of Energy, lowering your water heater temperature from 140°F to 120°F can reduce energy consumption by 6-10% annually. For a household spending around $400-600 per year on water heating, this adjustment could save $24-60 yearly.

Different household activities require different water temperatures. Washing dishes in a dishwasher typically requires 140°F to properly sanitize and dry dishes. Hand-washing dishes in a sink works fine at 120°F. Bathing and showering are comfortable at 110-120°F for most people. Laundry cleaning depends on the fabric—delicate items need cooler water, while heavily soiled items benefit from warmer temperatures.

Your water heater's temperature setting also affects safety. Water that is too hot can cause scalding injuries, especially for children and elderly people. The American Burn Association reports that a person can suffer third-degree burns in just one second when exposed to 156°F water. At 140°F, this takes about three seconds. At 120°F, it takes approximately ten minutes. This safety consideration is why many experts recommend 120°F as the optimal household temperature.

Practical takeaway: Before adjusting your thermostat, locate it on your water heater's exterior and note the current setting. This baseline information will help you understand what changes you're making and measure any differences you notice afterward.

Locating Your Water Heater's Temperature Control

Finding your water heater's thermostat is the first step in making adjustments. Water heaters can be located in basements, attics, garages, utility closets, or crawl spaces. Tank-style water heaters (the most common type in American homes) typically have a temperature control dial or digital readout mounted on the outside of the tank, usually near the bottom. Electric water heaters often have two thermostats—one on the upper heating element and one on the lower element. Gas water heaters typically have a single thermostat mounted on the side of the tank.

On a gas water heater, the thermostat control usually looks like a dial with temperature markings. It's often labeled with settings like "low," "medium," "high," or specific temperature numbers ranging from 80°F to 140°F. The dial itself is usually located behind a metal cover plate on the outside of the tank. To access it, you may need to remove this cover plate by loosening a screw or bracket. Some gas models have the control integrated into the main burner assembly, which sits at the base of the tank.

Electric water heaters present a different situation because they have multiple access points. These heaters have two heating elements—an upper one and a lower one—each controlled by its own thermostat. The thermostats are located behind access panels on the side of the tank. These panels are usually covered with insulation and a metal or plastic plate. You'll need to turn off the power to the water heater at the circuit breaker before removing these panels for safety reasons. Each thermostat typically has a temperature adjustment screw or dial that you can adjust with a flathead screwdriver.

For tankless water heaters (which heat water on demand rather than storing it), the temperature control is usually a digital display on the unit itself or an external control panel mounted on a wall. These units are becoming more common in new construction and renovations. Tankless models allow for more precise temperature control and typically have buttons or a dial to adjust settings. Some newer models can be controlled through smartphone apps or smart home systems.

Practical takeaway: Once you locate your water heater, take a photo of the temperature control and its current setting. If your water heater is in a difficult-to-reach location, make a note of how to access it safely so you can make adjustments without difficulty.

How to Safely Adjust Temperature on Gas Water Heaters

Adjusting the temperature on a gas water heater involves changing the thermostat dial setting. Before beginning, allow the water heater to operate for several hours without any adjustment so you have a stable baseline. Then, decide what new temperature you want to set. Most experts recommend 120°F as the standard household setting. If you need hotter water for specific purposes, you can set it slightly higher, but 120-130°F covers most household needs.

To adjust a gas water heater, locate the thermostat dial on the side of the tank. If it's covered by a metal plate, remove this plate by loosening the fastening screw. Look at the current temperature marked on the dial. To raise the temperature, turn the dial clockwise. To lower the temperature, turn it counterclockwise. Make small adjustments—typically a quarter-turn at a time—rather than making large changes. After each adjustment, wait 15-20 minutes and then test the water temperature at your tap to see if it has changed appropriately.

Never attempt to adjust a gas water heater's thermostat if you smell gas, see visible damage to the tank, or notice rust or corrosion around the base. These are signs of potential problems that require professional attention. Additionally, some newer gas water heater models have electronic controls rather than mechanical dials. These units may have a digital display with up and down buttons to change the temperature setting. Consult your owner's manual for specific instructions for your model.

Testing your adjustment is crucial. Fill a glass with hot water from the nearest tap (the tap furthest from the water heater takes longest to run hot) and use a reliable thermometer to measure it. If you have access to an instant-read thermometer, this gives you accurate feedback about whether your adjustment is working. Wait at least 30 minutes after making an adjustment before testing, as it takes time for the adjusted temperature to reach your fixtures. Once the temperature stabilizes at your desired setting, you've completed the adjustment. Make a note of where the dial points so you can reference this setting in the future.

Practical takeaway: Start by adjusting your thermostat to 120°F if it's currently set higher. Monitor your water temperature for one week and note how this affects your daily routines and comfort levels. You can always readjust if needed.

How to Safely Adjust Temperature on Electric Water Heaters

Electric water heaters require a different approach because they have two heating elements, each with its own thermostat. Before adjusting either thermostat, turn off the power to the water heater at the circuit breaker. This is a critical safety step—working on an electric water heater while power is on risks electrical shock. After turning off the power, wait five minutes before proceeding. This allows any residual electrical charge to dissipate.

Locate the upper and lower access panels on the side of your electric water heater. These panels are typically about 4-6 inches square and covered with insulation. Use a screwdriver to remove the metal or plastic cover plate. Beneath this cover, you'll see the heating element and the thermostat, which looks like a small rectangular box with a temperature adjustment screw. To maintain consistent water temperature throughout your tank, both thermostats should be set to the same temperature. Most households should set both to 120°F.

The thermostat adjustment screw on an electric water heater is typically a flathead screw located on the front of the thermostat unit. Using a flathead screwdriver, gently turn the screw clockwise to raise the temperature or counterclockwise to lower it. Make small adjustments—a quarter-turn represents roughly a 5-10 degree change depending on your specific model. After adjusting both thermostats, reinstall the cover plates and insulation, then turn the power back on at the circuit breaker.

Allow your water heater to run for 2-3 hours after you turn the power back on so the heating elements can heat the water to your new temperature setting. Then test the hot water at various taps