ATT000014General Instructions for Flushing
Residential Hot Water Tanks
 
If there is dirt water coming from your hot water taps but your cold water taps are clear, you may need to flush out your hot water tank. If so, these instructions will generally apply to hot water tanks properly installed within the last 10-15 years. If you have ANY problems following these instructions, you should contact a plumber to help you in flushing your hot water tank.
  1. Turn OFF the power to the hot water tank. CAUTION: Power must be OFF before draining the hot water tank. The tank will be substantially damaged if there is no water in it and the power is ON.
     
  2. Connect a hose to the drain valve and direct it to a floor drain.
     
  3. Open the drain valve and flush the tank for about five minutes. CAUTION: At first, the water will be very hot.
     
  4. Shut off the cold water inlet.
     
  5. Open several hot water taps in the house to let air into the line in order to completely drain the tank.
     
  6. Turn the cold water inlet back on.
     
  7. Carefully close the drain valve as much as possible without forcing this valve shut. Due to age and possible rust in the valve, it may be difficult to shut it drip tight. Open the hot water supply valve to fill the tank, purging air through the open hot water taps.
     
  8. Open the drain valve again and flush until the water is running clear.
     
  9. Carefully shut the drain valve and the hot water taps in the house.
     
  10. Turn the power back ON.

Flushing Gas Hot Water Tank
14 Easy Steps for Flushing a Residential Gas Water Heater
  1. Turn the gas valve knob (A) to the pilot position.
    CAUTION: The valve must be in the pilot position before draining the hot water tank.
     
  2. Connect a garden hose to the drain valve (B). Note: Direct the hose to a floor drain or outside the house.
     
  3. Open the drain valve (B) and flush the tank for about 5 minutes.
    CAUTION:
    At first, the water will be very hot. 
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  4. Close the drain valve (B).
     
  5. Shut off water at the cold water inlet (C).
     
  6. Fully open a hot water tap in the house to relieve tank pressure and to completely drain the tank.
     
  7. Re-open the drain valve (B) and drain the tank.
    Note: This may take 30 minutes to 1 hour.
     
  8. Turn cold water tap on and off about 5 times for 1 minute to flush the sediment from the tank.
    Note: Continue doing this until the water is running clear.
     
  9. Close the drain valve (B) as much as possible without forcing the valve shut. (It may be difficult to completely close the valve due to age and possible rust in the valve.)
     
  10. Turn cold water inlet (C) on fully to refill the tank.
    Note: Make sure the hot water tap is still open. When the tank is full there will be a steady stream flowing from the open tap.
     
  11. Shut the water off at the hot water tap.
     
  12. Turn the gas valve knob (A) back to the On position.
     
  13. Disconnect the garden hose.
     
  14. Make sure that the drain valve (B) is completely turned Off.
    Note: If your valve drips after you have turned it off, you can install a cap, available at hardware stores.

    1/97 - Washington Natural Gas