Water Heater Repair
Water heater maintenance
Short answer
Water heater maintenance means flushing sediment from the tank, checking the anode rod that protects the tank from corrosion, testing the temperature and pressure relief valve, and checking the venting on gas models. It can extend the tank's life, especially with hard water, and it catches safety problems early.
Water Heater Maintenance at a glance
- Flush
- Commonly once a year; more often with hard water.
- Anode rod
- Checked every few years and replaced when mostly consumed.
- T&P valve
- Tested per the manufacturer's instructions; replaced if it drips or won't reseat.
- Tankless units
- Need descaling rather than flushing; see tankless water heaters.
Flushing sediment
Turn off the heat source
Gas to "pilot" or "vacation"; electric at the breaker. Let the water cool if possible; draining water is scalding hot.
Close the cold supply
Then open a hot faucet in the house to let air in.
Drain through a hose
Attach a hose to the drain valve, run it to a floor drain or outside, and open the valve.
Stir and repeat
Briefly open the cold supply with the drain open to stir sediment, until the water runs clear.
Refill before heating
Close the drain, open the cold supply, and wait until the hot faucet runs without sputtering before turning the heat back on.
On a heater that's never been flushed, old plastic drain valves can break or fail to reseal. If the tank is old and noisy, a plumber may advise against flushing a tank that heavy sediment is now sealing.
The anode rod
The anode rod is a sacrificial metal rod that corrodes so the steel tank doesn't. Once it's mostly consumed, the tank starts to corrode. Hard or softened water can use up anodes faster. Checking it means removing it from the top of the tank, which usually takes a large socket and sometimes considerable force, so many owners have a plumber do it.
Other checks
- Temperature setting: about 120°F is a common recommendation to balance scald risk and comfort.
- Venting (gas): the vent should be intact, sloped upward, and firmly connected. Soot or scorching near the burner needs a professional.
- Combustion air: don't store items against a gas heater or block its air supply.
- Drain pan and leak sensor: worth having where a leak would damage finished spaces.
- Expansion tank: if you have one, a plumber can check its air charge.
Problems that lead to water heater maintenance
Common questions
How often should a water heater be flushed?
Once a year is a common guideline, more often in hard-water areas. Check your manufacturer's instructions.
What happens if you never flush a water heater?
Sediment builds up, which can cause rumbling, reduce efficiency and capacity, and on electric models help burn out the lower element.