How To Drain And Flush Water Heater Tank?

Be careful when flushing water heater, avoid being scaled.

It’s a good idea to learn how to drain and flush water heater especially if you do not have a water softener or filtering to prevent hard water sediment buildup. We recommend:

Flush a quart of water from your tank two times a year. Flushing extends the life of your water heater, gives you more hot water and improves efficiency with planned maintenance.

  1. Turn the Knob on Your Hot Water Heater’s Thermostat to “Off”
  2. Turn off the electric or gas supply. 
  3. Put on rubber gloves to help avoid touching scalding water.
  4. You can do laundry or take a shower to help drain the hot water.
  5. Turn off the cold water supply lever to a 90 degree angle.
  6. Connect a garden hose to the water heater drain valve.
  7. Place the other end of the hose in a drain or outside. Remember, you are working with scalding water.
  8. Water heater won’t drain? Open the pressure relief valve and turn on a hot water faucet. This will break the vacuum and allow the water to flow out of the hose.
  9. Open the tank drain valve. HOT, dirty water should start coming out of the hose. Say half an hour to drain a water heater tank depending on the size. Can drain under 1 gallon per minute.
  10. When the water has been drained, close the Temperature & Pressure (T&P) relief valve and faucets before turning the cold water supply on. 
  11. Flush the water heater tank – open and close the cold water supply lever a few times. This should help flush out any remaining sediment in the tank. Flush water heater until you see clear water.
  12. Close the water heater drain valve and disconnect the hose from the valve. If the drain valve drips when closed you may need to buy a galvanized threaded cap to stop the leak. Sometimes the drain valve does not close completely, especially with plastic valves.
  13. Open the water heater cold water valve to fill the tank in about 10 minutes. 
  14. Turn on a hot water faucet to purge air out of the tank.
  15. When you start getting clear water instead of a cloudy air-water mixture, turn the hot faucet off.
  16. Turn the gas or electric water heater back on for warm, cozy comfort in about 40 minutes.  
  17. If you prefer a professional to drain and maintain you water heater, please contact your neighbors at PDM Plumbing, Heating, Cooling Since 1885. 815-726-6264.

Healthy, safe service visit.

PDM plumbers wear shoe covers, gloves, and a mask if you or they prefer. We wash hands prior to entry into your home, during and after. We practice social distancing, not shake hands and clean up well. It’s all part of PDM’s healthy service call.

PDM Water Heater King has been trusted in greater Joliet, Plainfield, New Lenox, Bolingbrook and SW Chicago Suburbs for 137 years.

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