Just a day or two ago my dual element electric 50 gal water heater started sucking. 6 months ago I had to replace the main thermostat. It wasn't turning off and getting to hot. But just recently it has less than half the amount of hot water. And it doesn't get as hot. This happened overnight. It wasn't a gradual thing. What could have gone wrong? Any help would be appreciated.

Check your elements for power. Sounds like one could be defective. What is the condition of your water? If it is high mineral content this could easily be your problem. Generally, If it is over 5 years old replace both of them. If you have bad water you may need to replace the Water Heater. Check with your water company or have your well water analyzed to know what to do.



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If the bottom elec element is bad then only the top element is heating the water. When this happens it will only heat the upper half of the tank and then will shut off because the top thermostat only senses the temp in the upper half. So you get half the hot water you should be getting.

Have someone check the bottom elec element. If the water heater is several years old and you have hard water in your area the mineral deposits/lime/calcium buildup may have covered the lower elec element.

There are four items that could cause the problem and if you NOT know how to test them contact a plumber who does. Thermostats are SELDOM the problem, (I have only replaced a handful in the past 65 years).

You could try this: turn off the power to your water heater. Cut off the water supply to your water heater. Drain your water heater all the way down until it's empty. Remove the anode rod. You can stick an inspection camera inside the hole that the anode rod was in. Make sure that your dip tube, located inside the tank, (on the cold water supply) has not fallen off or disintegrated. You can also check the functionality of your upper and lower thermostats and your upper and lower heating elements. You can find pretty informative videos on YouTube on how to test your thermostats and your elements. The other thing I would check would be what kind of faucets you have. Sometimes replacing your faucet cartridges will prevent water from mixing inside the faucet even when the faucet is off. I have known Moen and Symmons faucets to have this issue. Changing the faucet cartridges may remedy the problem.