How Often Should You Flush Your Water Heater?
There is no single flushing interval that is correct for every water heater. The best starting point is the maintenance guidance for your exact model, then adjust your attention based on water conditions, heater age, service history, and observed changes.
What changed: Tank Sediment no longer recommends blanket 6-month, 12-month, or 18-month schedules. Those numbers can be misleading without model-specific context.
What affects the maintenance interval?
- Manufacturer guidance: some heaters specify periodic draining, flushing, or descaling; others have different procedures.
- Water hardness: harder water can increase mineral scale, but hardness alone does not tell you exactly when a flush is needed.
- Heater type: storage tanks and tankless units use different maintenance procedures.
- Age and history: an older heater that has never been serviced deserves more caution than a recently maintained unit.
- Observed changes: unusual noise, reduced hot-water performance, discolored water, leakage, or corrosion may justify investigation—but they are not proof of sediment.
When should you avoid a blind flush?
If the heater has a long unknown service history, a stuck or deteriorated drain valve, active leakage, major corrosion, gas or electrical concerns, or you cannot confirm the proper shutdown/restart procedure, do not force a generic flushing routine.
What should homeowners use instead of a calendar rule?
Check the owner documentation, note the water conditions and service history, watch for changes, and ask a qualified technician what the manufacturer recommends for that specific heater when the situation is unclear.
Our maintenance context tool can help organize dates, hardness context, and observations. It does not measure sediment or prescribe a maintenance interval.
Related guides
See sediment removal options, flushing decision guide, and hard water and water heaters.