Turning on a hot water tap only to be greeted with ice-cold water can lead to extreme frustration. By knowing the cause of the problem you can usually have it repaired and the hot water back on in a short time.

Leaking or Empty Tank

The most obvious reason for no hot water is that the tank is empty and has no heated water to provide. In some cases, this could be because of catastrophic tank failure, which may go temporarily unnoticed if the heater is in an area you rarely visit, such as the basement. It's an easy problem to spot, though, since there will be water all around the heater on the floor and none in the tank.

The tank could also be empty if something is blocking a water line that feeds into the tank. You can check the water valve to verify that it is turned to the fully open position. Otherwise, you will need to have the water supply inspected. If the water heater is too small it could also be empty because someone else has already used all the available hot water and it needs to refill. In this case, you will hear the water heater bubbling and humming as water is flowing in and heating up. You may need a larger water heater in this case.

Failed Heating Elements

The heating elements are inside the tank. You may have an electric water heater with one or more heating elements, or you may have a gas heater which uses a burner system to provide heat to the tank. Electric elements will sometimes fail as they have a finite lifespan. A repair service can test each element to see if it is the problem. If it is, the elements are simple to replace and you can have your hot water again in a short time.

The burner system on a gas water heater requires a bit more maintenance. In some cases, all that is needed is a good cleaning of the fuel valve and the burner itself to make sure the gas is combusting properly. In other cases, the burner or the gas lines may require replacement.

Malfunctioning Thermostat

A malfunctioning thermostat on the hot water heater can give the wrong reading, which means that the heater may power down before the water is at the temperature desired. The first step is to check that the thermostat is set correctly. Generally, water heaters are set to temps around 120 degrees F.

If the temperature is at the correct setting and there is still no hot water heater, it's time to call in a repair service. They may need to recalibrate the thermostat so it works correctly. In some cases, the thermostat may require complete replacement.

Contact a water heater repair service for further troubleshooting or to schedule a repair.