Water HeatersIntermediate
Flush Water Heater Sediment
Time
60–120 min
Steps
5
Pre-check
3 items
Skill
Intermediate
Scope
Drain and flush a tank water heater to remove sediment buildup, restore efficient heating, cut popping noise, and extend the life of the tank and elements.
Safety
Read before starting
Turn off fuel/power and water; allow water to cool; route drain to safe location.
Pre-Check
3 items · complete before you start0 / 18 complete
Steps
Shut Down & Relieve Pressure
- Turn off breaker or gas control
- Close cold inlet valve
- Open a hot water faucet to relieve pressure
✅Continue Gate:Utilities off; pressure relieved?
Attach Hose & Drain
- Attach garden hose to drain valve
- Route to safe drain
- Open drain valve and let tank empty
✅Continue Gate:Tank fully drained to safe location?
Flush Sediment
- Pulse cold inlet to stir sediment
- Drain again until water runs clear
- Repeat 2–3 cycles as needed
Close & Refill
- Close drain valve; remove hose
- Open cold inlet
- Keep hot faucet open until steady flow (air purged)
✅Continue Gate:Tank full and air purged?
Restore & Check
- Restore power/gas and relight/ignite per manual
- Check for leaks at drain valve and connections
- Set temp to 120°F typical
Code notes
- Max hot-water temp at lavatories/showers/tubs: 120°F via ASSE 1016 / ASSE 1070 thermostatic mixing valves.
- Closed systems (PRV, check, or backflow on cold inlet) require a thermal-expansion tank — IPC §607.3 / UPC §608. California also requires seismic strapping per CPC §507.