Who used all the hot water?! Maybe your home's gas water heater just isn't keeping up with demand. Or maybe it has "issues," such as a pilot light that won't stay lit or a bunch of gunk that comes out with the hot water. No problem--because you are a member in good standing of the Fix-It Club!

How Does It Work?

A natural or propane gas water heater uses a burner to heat water in the tank for distribution throughout the home.

A water heater is an apparatus for heating and storing hot water. A water heater typically warms water to a temperature between 120° and 140°F. When a hot-water faucet is opened, hot water flows from the top of the tank toward the faucet, and cold water enters via the dip tube to replace it. The fuel for heating the water heater can be natural gas or propane, or it can be electricity (see Electric Water Heater Fix-It Guide ).

As the water temperature inside the tank drops below the setpoint, the thermostat opens a valve that sends gas to the burner, where it is ignited by a pilot flame or electric spark. Combustion gases are vented from the burner chamber through the flue and its heat-retaining baffle, then out the draft hood and vent. If the temperature or water pressure rises too high inside the water heater, a relief valve opens to prevent the tank from exploding.

What Can Go Wrong?

The pilot light may be out or may not stay lit. There may not be enough hot water, or the water may be too hot. The water heater may leak or be noisy, or the hot water may be dirty.

Fix-It Tip

A problem with your water heater may be due to overwork, not mechanics. If your water heater holds less than 15 gallons per family member (tank volume is stamped on a metal plate affixed to most water heaters), consider a larger unit or staggering your use of hot water.