Laundry room with a tank-type water heater beside the washer
Generic photo: Alex Tyson · Pexels License

Tank water heater sediment flush

Sediment settles at the bottom, insulating gas burners and burying electric lower elements. Flush through the drain valve; heavily scaled tanks may need repeated flushes.

Single source ~45 min easyBrands: All

Before you start

  • Electric: breaker off before draining (never power dry elements)
  • Gas: set control to pilot/vacation; no gas work
  • Scald risk

Diagnostic steps

Unlock all 4 steps with expected values

Full library + AI assistant for $34.90, one time.

Get lifetime access

OnCall Tech is a reference tool for trained technicians and can make mistakes. Always disconnect power and confirm with the manufacturer's documentation before you work.

More water heaters guides

Guide · Water Heater

Heat-pump (hybrid) water heater: slow recovery, noise, errors

Hybrids need enough room air and a clean air filter, a working condensate drain and the right mode. Many complaints are mode settings or a dirty filter. Refrigerant faults are sealed-system work.

5 steps ~60 minmoderate
Guide · Water Heater

Tankless water heater descaling (flush)

Scale insulates the heat exchanger, causing overheat codes and fluctuating temperature. Flush with a pump and descaling solution through the isolation valves.

5 steps ~75 mineasy
Guide · Water Heater

Hot water recirculation pump problems

Check timer/settings, check valves, air in the loop and the pump itself. On tankless units with built-in pumps, a recirculation code may point to air or a leak in the loop.

5 steps ~60 minmoderate
Tank water heater sediment flush · OnCall Tech