Maintenance ScheduleHome
How often should you flush a water heater?
Sediment settles on the bottom of the tank, insulates the burner or element and makes the heater work harder. Hard water and a busy household build it up faster.
The answer
Flush a tank water heater every 6 to 12 months, and at least once a year.
Range: 6 to 12 months · checked 6 November 2026
Typical interval
What changes it
- Hard water: more sediment, so flush nearer every 6 months.
- A tankless heater has its own descaling routine, usually once a year in hard water.
- A rumbling or popping sound from the tank is a sign of sediment.
- The anode rod should be checked at the same time; it protects the tank from corrosion.
Do it
- Turn off the power or gas and let the water cool.
- Connect a hose to the drain valve and run it to a drain or outside.
- Open a hot tap to let air in, then open the drain valve and let the tank empty.
- Open the cold inlet briefly to stir and flush the sediment, then close the drain and refill.
- Restore power or gas only when the tank is full.
Put it in your schedule
The maker opens with Water Heater Flush at every 12 months.
No account. The maker keeps the job in your browser and in the link.
Why this interval
The sources below give the full picture. The factors above are the ones that move the interval for most situations.
The range is a starting point, not a rule for every situation. The factors above are the ones the sources name; if your situation is different, use the range and ask a professional where the job needs one.
If you want the job in a schedule with reminders, open the schedule maker with this job already loaded. The how often index has the other jobs.
Water Heater Flush questions
What changes the interval?
Hard water: more sediment, so flush nearer every 6 months. A tankless heater has its own descaling routine, usually once a year in hard water. A rumbling or popping sound from the tank is a sign of sediment. The anode rod should be checked at the same time; it protects the tank from corrosion.
Does the app use this interval?
The app’s ready-made schedule uses every 12 months. You can change it on the job.
Where does this come from?
The answer is checked against 2 primary sources, linked under Sources with the date each was read.
Sources
The interval and the factors on this page are checked against these sources.
- How to drain and flush a water heater. A. O. Smith.Six-monthly flushing in A. O. Smith’s maintenance guidance. Checked 6 November 2026.
- Residential electric water heater installation and use guide. A. O. Smith.At least annual flushing for a residential tank, more often with hard water. Checked 6 November 2026.