Water system flushing is one of the tools many water agencies use to ensure the water quality remains at the highest level and each customer always receives safe and healthy drinking water. During a flushing operation, you will see city crews flushing via fire hydrants.

In order to properly conduct flushing operations, the water flowing in the pipes must reach maximum velocities. These higher than normal velocities will scour the insides of the distribution piping, helping to clean out any biofilms or silt that may be present.

In most cases, it’s not possible to capture and reuse the water being flushed due to the high velocity and volume of water being released. To make sure we are using water wisely, we use best management practices to ensure that no more water than needed is flushed out of our pipes.

Why flushing is important

• Bacterial Control: Biofilm growth in drinking water systems can occur when an area becomes stagnant. This can be eliminated through flushing.
• Taste & Odor Control: Flushing removes many of the mineral deposits and sediment that naturally accumulate in the water mains which can affect taste and odor.
• Corrosion Control: Flushing introduces higher than normal water velocities. This ensures that the inside of the piping is scoured and, thus, reduces corrosion.
• Fire Hydrant & Valve Exercising: Operating fire hydrants and valves helps to ensure that they’ll work properly in an emergency.

Discoloration of water

Residents in the immediate vicinity of the work may experience temporary discoloration of their water. This discoloration consists primarily of harmless silt and naturally dissolved iron which are stirred up during flushing; it does not affect the safety of the water. If you experience discoloration in your water after the flushing exercise is being done in your area, you can clear the pipes in your home by running all water faucets for a few minutes until they run clear. If the discoloration of water persists, please contact the city Water Quality Specialist at 714-738-2835.