Flushing your water heater, and when to stop and call someone

Memphis has some of the best tap water in the country — soft, clean, straight out of the Memphis Sand aquifer — so you are not fighting the mineral scale that plagues other cities. Even so, fine sediment settles into the bottom of a tank over the years. It insulates the burner or element from the water above it, which means longer run times, higher bills, and a tank that wears out sooner.

Once a year, do this:

1. Turn off the heat. On an electric heater, switch off its breaker. On a gas heater, turn the thermostat dial to "Pilot" or "Vacation".
2. Let it cool. An hour at least. Longer is better. Scalding is the main risk in this whole job.
3. Connect a garden hose to the drain valve at the base and run it somewhere that can take very hot water safely — a driveway or a floor drain, not a flower bed.
4. Open a hot tap somewhere in the house to let air in, then open the drain valve.
5. Run it until it comes clear, usually a few minutes. Close the valve, remove the hose, let the tank refill fully, then restore power or set the thermostat back.

While you are there, test the temperature and pressure relief valve — the lever on the top or side. Lift it briefly and let it snap back. It should discharge a little water and reseat cleanly. If it keeps dripping afterwards, it needs replacing; that valve is the one thing standing between a failing tank and a serious accident.

Set the thermostat to 120°F. Hotter than that scalds faster than most people expect and costs more to maintain.

Signs the tank is near the end: rusty or metallic-smelling hot water, a rumbling or popping sound when it heats, or any moisture around the base. Most tanks last eight to twelve years.

Call someone if: the work involves gas connections, the relief valve drips after testing, you see water pooling at the base, or the tank is past a decade old and you would rather plan a replacement than be surprised by one.