A Guide to Flushing Water Pipes

LADWP delivers safe, high-quality drinking water from our distribution system to your property’s water meter, but maintaining the high quality of our water from your meter to the tap requires property owners to take the proper steps. Following weeks or months of inactive water use, we recommend you flush your property’s water pipes to clear out sitting water and accumulated sediments. Below are some general guidelines to help you safely and effectively flush plumbing, faucets, toilets, and other fixtures on your property. For large commercial properties, please also consult your property or building manager for more information.

1.    Prepare your site for flushing. Remove aerators and screens from all faucets. Set water-softening devices and filters, both point-of-use and whole-house, to “bypass mode.”
2.    Flush outside plumbing. Open and flush any external fixtures and hose bibs until water is clear and temperature is constant.
3.    Flush cold water. Run all cold-water faucets on the property beginning with the faucet closest to the water line. Let all run at the highest flow (or fully open) until water is clear and temperature is constant. Then turn off all faucets in reverse order. 
4.    Flush all toilets and urinals. Do this at least once, but repeat if the refilled water is not clear.
5.    Flush hot water. Drain your hot water tank to discharge any accumulated sediments. Wait for the hot water tank to refill and flush as in Step 3.
6.    Clean aerators and screens and reattach to faucets, shower heads, and fixtures.
7.    Flush any water-using appliance or run a cycle. This includes the washing machine, dishwasher, and refrigerator/ice maker.
8.    Restore all removed filters and reset all water devices from “bypass mode.”

More information and guidance is available in the American Water Works Association (AWWA) and International Association of Plumbing and Mechanical Officials’ (IAPMO) 2022 Manual of Recommended Practice for: The Safe Closure and Reopening of Building Water Systems.