A water heater tends to run silently in the background for years, right up until sediment buildup or a corroded anode rod cuts its life short. Maintain a water heater with two recurring tasks — an annual flush and a periodic anode rod check — and you head off the two most common reasons tank-style heaters fail before their time.
Flush the tank once a year
Sediment (minerals from your water supply) settles at the bottom of the tank over time. It insulates the water from the heating element or burner, forcing the unit to work harder and longer to heat the same amount of water, and it eventually causes rumbling or popping noises as trapped water boils under the sediment layer.
- Once a year is the standard flush interval for most households.
- Twice a year (roughly every six months) if you have notably hard water, since mineral buildup accumulates faster.
To flush a standard tank water heater:
- Turn off the power (electric) or set the gas valve to "pilot" (gas) before starting.
- Turn off the cold water supply valve feeding the tank.
- Connect a garden hose to the drain valve near the bottom of the tank and run it to a floor drain or outside.
- Open the drain valve and a hot water tap somewhere in the house to let air into the system, then let the tank drain fully.
- With the drain valve still open, briefly turn the cold water supply back on to stir up and flush out remaining sediment, then let it drain again.
- Close the drain valve, refill the tank, and only restore power or relight the pilot once the tank is completely full — running a heating element dry can destroy it.
Check the anode rod every couple of years
The anode rod is a sacrificial metal rod inside the tank that corrodes on purpose, so the tank itself doesn't. It's the single part most responsible for how long a tank lasts once it's protecting bare metal instead of a fresh rod.
- Check it roughly every two to three years, sooner if you have a water softener, which tends to accelerate anode rod wear.
- To inspect it, locate the hex head on top of the tank (sometimes under a cap), unscrew the rod, and pull it out.
- Replace it if it's worn down to less than about half its original thickness, or if you can see bare steel wire core showing through — that means the aluminum or magnesium coating is essentially gone and the rod is no longer doing its job.
A simple annual routine
- Test the temperature-pressure relief (T&P) valve by lifting its lever briefly and confirming water discharges, then closing it again — this valve is what prevents dangerous pressure buildup.
- Set the thermostat to around 120°F, which balances scald safety with energy use and slows mineral scale formation compared to higher settings.
- Flush the tank to clear sediment.
- Inspect the anode rod every couple of years and replace if heavily corroded.
- Check for rust, corrosion, or leaks around fittings and the base of the tank.
- Clear the area around the unit of stored items, especially anything flammable near a gas unit's burner compartment.
The takeaway
A water heater's maintenance list is short but matters: flush it annually to keep sediment from insulating and overworking the tank, and check the anode rod every couple of years so it keeps sacrificing itself instead of the tank wall. Skip both long enough and you're not looking at a tune-up anymore — you're looking at a full replacement, years earlier than it should have been necessary.
