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Flushing your home water lines

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OKC Utilities crews have completed flushing out water lines that became filled with sediment when a 30" was reconnected to the water system after being relocated. The sediment is made up mostly of lime, calcium, and chlorine residuals.

Residents in the area may flush their residential water systems to push out any remaining sediment.

  • Basic flushing instructions are below
  • A printable PDF with the instructions is also available

Flushing Instructions

Complete these steps in the order directed below. Finish each step completely before moving on to the next. 

Remove Aerators
Remove the screens (aerators) from the end of each faucet before flushing and let them soak in bleach to
remove any dislodged organic matter. With the aerators removed, begin the flushing process.

Flush ALL hot water taps for 15 minutes
Run ALL hot water taps in the building at least 15 minutes or until the hot water runs out. This includes hot water taps at kitchen and bathroom sinks, bath tubs and showers, and any other hot water fixtures in the home. This will also ensure your water heater will be completely flushed with fresh, chlorinated water from
the water system’s lines.

Flush ALL cold water taps for 5 minutes
Once the hot water tank and hot water lines have been flushed, open ALL the cold water fixtures and run them for at least FIVE MINUTES, including those in the kitchen, bathroom, and other areas (wet bar, utility room sink, etc.). Also, flush each toilet at least one time, and clean them using a regular toilet cleaner and disinfectant. If your home is more than one story, start with the faucet(s) that are highest up in your home to ensure water gets pulled to them first, then open the other faucets, once at a time, moving from highest floor to lowest floor.
Disinfect sink and tub drains
Run cold water into the drain for about 15 seconds then turn the water off. Pour 1 to 2 cups of chlorine bleach down the drain, making sure to pour around the edges of the drain so that it runs down the sides. Be careful not to let the bleach splash or drip on skin or clothing. Leave bleach in the drain for about 10 minutes then flush with hot water for 2 minutes to ensure all bleach is removed. If you have a garbage disposal, turn it on while flushing to ensure it is completely flushed. 

Flushing your hot water heater
Water heaters should be flushed every 1 to 3 years, depending upon the make and model, to help control the build-up of mineral deposits. Flushing will help the water heater operate more efficiently, and can help extend its life. 

It’s a good idea to flush the water heater if the water becomes yellow or brownish, or if you notice sand-like mineral sediments or calcium build-up that appears as white, flaky particles in the fixtures.
To flush your hot water heater, follow these instructions: 
1. Turn off electric power or gas to the water heater.
2. Shut off the cold water inlet to the tank.
3. Attach a garden hose to the tank drain valve located near the bottom of the tank. The drain valve usually looks like a regular garden faucet or a round dial with a threaded hole in the middle.
4. Extend the garden hose to a place where the water can safely exit the heater.
5. Open the pressure relief valve or turn on a faucet in the house to allow air in the tank.
6. Open the drain valve to allow the water to exit the tank. Caution: water leaving the heater will be hot and under normal household water pressure.
7. After 5 minutes of flushing, fill a bucket with the still flushing water.
Allow the water in the bucket to stand for 1 minute. See if the water is clear, or if any sand-like material settles to the bottom. If the water is clear, go to step 9. If the water is discolored or you see sand-like material at the bottom of the bucket, repeat steps 6 and 7 until the flushed water is completely clear and free of sediment.
8. Close the drain valve and remove garden hose. Turn off the inside faucet, close the pressure relief valve,  and turn on the cold water inlet.
9. Turn on the gas or electric power to the tank.

If you are not comfortable flushing the hot water heater, another option is to hire a licensed plumber.

For more information, call the Utilities Public Information office at 297-3363.