How to Flush Supply Water Pipes

Updated April 17, 2017

Flushing water supply pipes regularly ensures that your home's water is free from potentially harmful quantities of bacteria and contaminants. Water supply pipes can develop layers of bacterial growth over time that can affect the quality of water in your home. When pipes are not regularly flushed, the water will sit in the dirty pipes and become contaminated. Ensure that your water is clean and safe by regularly flushing your water supply pipes.

Perform the cold water flush. Flush the cold water pipes by turning on the faucet and allowing the water to run for one to two minutes. Feel the water to ensure that it is very cold. Cold--not just cool--water is a sign that the water running through your faucet has not been sitting in the pipes for an extended period of time. Perform this test for every faucet in your home to ensure that the water you are using has been properly cleaned and sanitised.

Perform the hot water flush. Turn on the hot water faucet and allow it to run for 15 minutes if you have a 40-gallon tank or for 30 minutes if you have an 80-gallon tank. Flushing the hot water tank allows the tank to drain and fill again with fresh water. Repeat this test with all faucets in your home to properly flush all water lines.

Run the dishwasher, washing machine and shower for one to two minutes. Allowing your appliances to flush as well ensures that all lines have been completely cleaned.


Contact your local sanitation department for recommendations on how often you should flush your water pipes.


Flushing your water pipes may not remove all harmful chemicals from the water. Use a water filtration system for drinking water.

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About the Author

Based in Colorado, Gisela Chavez has been writing and editing since 2004. Her editorial experience ranges from editing technical documents to editing for “The Bloomsbury Review.” She earned a professional writing certificate from the University of Colorado, where she received a Bachelor of Arts in English and Spanish.