You can extend the life of your water heater-and save energy and money-by draining it every three to six months to remove any sediment that has built up at the bottom of the ... read full tip

You can extend the life of your water heater-and save energy and money-by draining it every three to six months to remove any sediment that has built up at the bottom of the tank. Sediment blocks the flow of heat from the burner, which means more energy is required to heat the water.

Even a half-inch of sediment sitting in a gas or propane water heater cylinder will increase your fuel usage by 60 to 70 percent. In other words, the average household may be spending an extra $125 or more per year just because there's dirt and grime in the water heater.

If every U.S. home with a gas water heater had a half-inch of sediment in its tank, we'd need an extra 781 billion cubic feet of natural gas per year to heat our water-equivalent to the total amount of energy consumed annually for that purpose by nearly 45 million households.

Plumbing Systems and Design
Department of Energy (PDF)
Duke Energy