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1. What are ACWD's sources of supply?

Runoff from the Alameda Creek watershed - 40%
State Water Project - 40%
San Francisco's Hetch Hetchy System - 20%

2. Why are some fire hydrants open with water discharging?

ACWD cleans water mains to remove the buildup in pipes that may cause discolored water. This is accomplished by opening fire hydrants. As the water flows at high velocities through the mains, scale and fine sediment are dislodged. The resulting discolored water leaves the distribution system through the open fire hydrants. Since some of this water eventually flows into San Francisco Bay, ACWD utilizes disinfectant and sediment removal best management practices to minimize impacts to the environment.

To learn more about the main cleaning program, please visit: www.acwd.org/maincleaning.

3. Why doesn't ACWD recapture the water discharged from fire hydrants in the Main Cleaning Program?

Prior to resuming the main cleaning program this year, ACWD staff thoroughly examined possible recapture methods for main cleaning discharges and will continue to do so. As much as ACWD would like to be able to reuse water from the main cleaning program, unfortunately, in most cases, it’s just not technically feasible. In order to clean our mains and continue to ensure high quality water for our customers, we need to flush at very high flow rates that are not possible to recapture. The amount of trucks, transit time for the trucks, gas, etc. needed to recapture the water would be excessive. Directing the water to a truck would be very time-consuming and resource intensive, significantly increasing costs of these State-required processes.

To learn more about the main cleaning program, please visit: www.acwd.org/maincleaning.