Check for defective dip tubes
The role of the dip tube is to direct incoming cold replacement water to the bottom of the tank for heating. While it warms, the dense, cold water stays naturally segregated from the warmer, lighter water floating on top. The water for faucets and appliances comes from the hot layer on top. If the dip tube is missing, the cold incoming water mixes with the hot water at the top of the tank and you wind up feeding the house with tepid instead of hot water.
If you’re having hot water problems, first see if you have a water heater made during those bad dip tube years. Often, the first four numbers on the serial number are the month and year of manufacture. If the third and fourth numbers are 93, 94, 95, 96 or 97, it could be affected. If you have a bad unit, there are two options. First, replace the water heater and flush all the faucet screens and filters throughout the house. (If yourwater heater is more than 10 years old, it’s nearing the end of its life, so it’s probably worth replacing.) New water heaters have dip tubes that’ll last as long as the water heater.
Or second, replace the defective dip tube with a cross-linked polyethylene one and flush the debris out of the water heater and the screens and filters. You may have to flush the system more than once.