Electric Water Heater: Fluctuating water temperatures

In an electric water heater, the upper and lower thermostats must fit snug against the side of the tank to sense and regulate the temperature correctly. Turn off the power to the water heater and remove the access covers to check the thermostats' positions. Adjust the thermostat brackets if necessary to keep the thermostats snug against the tank.

A failed thermostat or heating element in an electric water heater can also cause hot water temperature fluctuations. If water temperature fluctuates below the set temperature, check for failed heating elements and thermostats. If the water heater tends to overheat the water, find the cause of overheating. Replace any failed thermostats and broken heating elements.

Sediment build-up at the bottom of the tank can cause hot water temperature fluctuations. If it's been more than a year since you drained sediment from your water heater tank, now's the time to clear sediment from the tank. A broken dip tube that carries cold supply water to the bottom of the tank will cause temperature fluctuations. Replace the dip tube if broken. Some water heaters don't have a replaceable dip tube. If you can't replace the dip tube, replace the entire water heater.

electric water heater

These repairs may help solve your electric water heater problem

Replace the water heater heating element

Replace the water heater heating element

The heating element is the heat source inside an electric water heater. It extends directly into the tank, where it radiates heat energy to the water around it. If the heating element is not heating when activated, replace the heating element.

How to replace an electric water heater heating element

If your electric water heater runs out of hot water quickly, or if the water isn't as hot as it should be, the heating element could be the problem. This step-by-step repair guide and video show how to replace a water heater heating element.

Repair difficulty
Time required
 30 minutes or less
Read more
Replace the water heater thermostat

Replace the water heater thermostat

The thermostat constantly monitors water temperature in the tank. When the water temperature drops beneath the desired setting, the thermostat sends power to the electric heating element or gas burner to begin heating. If the thermostat isn't sending power to the heating element, replace the thermostat. In a gas water heater, replace the gas control assembly that contains the thermostat.

How to replace an electric water heater thermostat

If your electric water heater makes the water too hot or not hot enough, the thermostat could be broken. This DIY repair guide and video show how to replace an electric water heater thermostat.

Repair difficulty
Time required
 30 minutes or less
Read more
Replace the water heater drain valve

Replace the water heater drain valve

The drain valve threads into the bottom side of the tank and is opened to drain and flush out sediment from inside the tank. Replace the drain valve if it leaks or won't open to drain the tank.

July 1, 2015
By Lyle Weischwill
How to replace a water heater drain valve

If your water heater is leaking from the drain valve, follow the 6 quick steps in this DIY repair guide and video to replace the drain valve.

Repair difficulty
Time required
 30 minutes or less
Read more

Symptoms common to all water heaters

Choose a symptom to see related water heater repairs.

Main causes: water supply needs chlorine treatment, anode rod too reactive
Main causes: thermostat temperature set too high, thermostats need adjustment, faulty thermostat, shorted heating element
Main causes: thermostats need adjustment, water heater capacity too low, bad heating element, thermostat failure, excessive tank sediment
Main causes: lack of power, no gas supply, thermostat limit switch tripped, bad element, bad thermostat, gas valve failure, bad thermocouple
Main causes: broken heating element, thermostat failure, excessive tank sediment, tank size too small, burner valve assembly failure
Main causes: faulty pressure relief valve, water is overheating
Main causes: loose water pipe fittings, leaky drain valve, bad temperature-pressure relief valve, leaky heating element, cracked tank

Repair guides for electric water heaters

July 1, 2015
By Lyle Weischwill
How to replace a water heater drain valve

If the drain valve on your electric water heater is leaking water, replace it following these step-by-step instructions.

Repair difficulty
Time required
 30 minutes or less
How to replace an electric water heater anode rod

If your hot water begins to smell like rotten eggs, replace the anode rod with a zinc-aluminum anode rod following the instructions in this repair guide.

Repair difficulty
Time required
 30 minutes or less
How to replace an electric water heater thermostat

If the water temperature fluctuates or you don't get enough hot water, follow these instructions to replace your water heater's thermostat.

Repair difficulty
Time required
 30 minutes or less

Articles and videos common to all water heaters

Use the advice and tips in these articles and videos to get the most out of your water heater.

November 1, 2018

How to read a wiring schematic video

By Sears PartsDirect staff

Learn how to decipher symbols so you can buy the right part for your problem.

October 31, 2018

Cleaning your appliances after a drinking water advisory

By Julie Riebe

Find out how to clean and flush household appliances once a boil water advisory is lifted.

August 1, 2015

Water heater common questions

By Sears PartsDirect staff

These common questions and answers can help you make the most of your water heater.