Periodic fire hydrant flushing is necessary to ensure proper functioning of the fire hydrants and to purge the water distribution system of sediment.

Residents may experience some decrease in water pressure, as well as possible degradation of water clarity during or shortly after this maintenance program.

Questions regarding this important maintenance program should be directed to the Water Quality Department at (650) 355-3462, Monday-Friday 8:00 a.m. – 4:30 p.m.

Here are some common frequently asked questions about hydrant flushing:

Q. What can I expect during flushing?
A. If tap water is used during flushing, it could be rust colored and include fine sediment. If your water does become discolored, turn on an outside faucet to clear the water line before doing any cooking, laundry or cleaning. Check the clarity by running cold water for a few minutes, allowing new water to work its way into your pipes. In some cases, you may experience slight discoloration for a few hours. This discoloration only affects the appearance of the water; it does not affect water quality. It is best not to use hot or warm water until the water has returned to normal.

Q. What should I do if my water pressure or volume seems low after flushing?
A. Low water pressure is expected during flushing. However, if you still have low pressure or low water volume after flushing, check your faucet and washer screens for trapped debris. If your faucets are clear, and you still experience low pressure, please contact the District to report the issue.

Q. Why does the water look different after hydrant flushing?
A. When a hydrant is opened, there will always be temporary incidences of discolored water containing fine sediment particles. There is no health hazard associated with discolored water. Allow a few hours for discoloration to dissipate. To verify the water has settled, allow your cold water tap to run until clear.