Electric water heater with no hot water? What to check first

This guide is for electric tank water heaters. The checks come from the manufacturers' own manuals, easiest and safest first. It does not cover gas water heaters: for those, contact the manufacturer or a licensed pro. If you smell gas, leave the house and call your gas utility.

Safety first. A.O. Smith warns that working near an energized circuit can cause severe injury or death from electrical shock, and tells you to turn the water heater's circuit breaker off and check with a non-contact circuit tester that the power is off before opening the covers. Rheem says not to attempt repair of electrical wiring, the temperature sensor, the electronic control, heating elements or other safety devices, and to refer those repairs to qualified service personnel. Rheem and Bradford White also say not to turn the heater on unless the tank is full of water. Sources: A. O. Smith, Residential Electric Water Heater Use & Care Guide and Rheem, Electric Residential Water Heaters manual.

What to check, easiest first

1. Is it just recovering? Rheem lists "water usage may have exceeded the capacity of the water heater" and says to wait for the heater to recover after an abnormal demand. In winter, Rheem notes that colder inlet water takes longer to heat, which is normal.
2. Check the breaker or fuse. Rheem: "A fuse is blown or a circuit breaker tripped. Replace fuse or reset circuit breaker." Also make sure the electric supply and any disconnect switch near the heater are ON. A.O. Smith lists "no electric power" as the most likely reason for no hot water, a common problem on new installations. If it trips again, stop and call an electrician.
3. Check the thermostat setting. Rheem lists a thermostat set too low as a cause. Bradford White says its thermostats are factory preset to about 120°F (49°C), and A.O. Smith says water can scald even at 120°F; Bradford White adds that scalding can occur within five seconds at 140°F (60°C). Do not raise it casually. The manuals' scald fix is a thermostatic mixing valve. Adjusting the setting means turning off the circuit breaker and opening the access panel, so follow your manual or have a professional do it.
4. Make sure all faucets are closed. Rheem lists leaking or open hot water faucets. A.O. Smith adds that even a small leak on the hot side of your plumbing can make the heater seem to produce little or no hot water.
5. Know about the ECO (energy cut off). Rheem and A.O. Smith both describe a safety limit that cuts power to the heating elements if the water gets too hot, and a tripped ECO means no hot water. It must be reset by hand, and both manufacturers say the cause has to be found before the heater goes back into service: Rheem says it "must be investigated by qualified service technician and corrective action must be taken", and A.O. Smith says not to turn the power back on until the cause of the overheating has been identified and repaired. So if you suspect a tripped ECO, call a qualified pro first. Where the reset button is, and how to reach it, depends on the model (Rheem and A.O. Smith describe it on their electronic-control models), so follow your manual. Bradford White describes the same manual-reset limit device.
6. Check for an auto shutoff valve. Only if your heater has a LeakGuard or LeakSense system: Rheem says a closed auto shutoff valve causes no hot water, and the knob must be turned to OPEN with the power off.

Not enough hot water, rather than none? A.O. Smith lists a thermostat set too low, a heater that is too small for your household, a faulty thermostatic mixing valve in a shower or faucet, reversed plumbing connections or a melted dip tube on a new installation, and a failed lower heating element (you will have some hot water, but less than before). Sediment: A.O. Smith recommends draining and flushing the tank after the first six months of operation to see how much has built up, while Bradford White says to drain it at least once a month until the water runs clear. These are different brands' own advice, so follow your manual. Before draining, turn off the power and the cold water supply (Bradford White says to shut off the electric power whenever the water supply is off) and let the water run cool first: A.O. Smith warns about scalding.

When to call a pro. Call a licensed electrician or plumber if the breaker keeps tripping, if the heater still has no hot water after these checks, or if you think the ECO has tripped. A.O. Smith says a qualified person should check the heating elements and thermostat when the ECO has tripped, and lists a burned-out element and a broken thermostat or wiring among the likely causes of no hot water. Do not open the electrical parts yourself.

The exact steps differ by brand and model, so follow your owner's manual. Not sure of your model? See how to find your model number and how to find the manual.

Rheem, A. O. Smith and Bradford White are trademarks of their respective owners. HomeGear isn't affiliated with or endorsed by them. Bradford White source: Electric Water Heater Installation and Operation Manual.

Common questions

• Why is there no hot water but the breaker is fine? Common causes in the manuals are a tripped ECO, a burned-out upper heating element or a bad thermostat. Those need a qualified person.
• What does a tripped ECO mean? A.O. Smith says in most cases the tank overheated because of a problem with one of the elements or the electronic thermostat, so have a qualified person check it before power is restored.