Main Cleaning

2019 Main Cleaning Program - Important Information

The Alameda County Water District (ACWD) is scheduled to clean a selection of water mains in the cities of Fremont and Union City, and all dead-end mains in the Tri-Cities to improve water quality and remove sediment buildup in pipes that may cause discolored water. This is part of the vital service provided by ACWD to ensure that all customers receive high quality water.

Cleaning will occur at various locations throughout the service area from January through July 2019; Monday through Friday, from 7 a.m. to 4 p.m. (excluding holidays). Please be aware that the main cleaning schedule is subject to change.

To find out if, and when the water main on your street will be cleaned, click the link by city below. Streets are sorted alphabetically:

2019 Main Cleaning Street List - Fremont

2019 Main Cleaning Street List - Newark

2019 Main Cleaning Street List - Union City

Tip: To quickly search your street, on your keyboard press Ctrl+F and type your street name into the search box; then press 'Next'. If your street is scheduled to be cleaned this year, the street name will be highlighted. Please note that some streets may have two cleaning dates due to two different cleaning events (water main cleaning and dead-end water main cleaning).

Visit the map to find out if and when your street will be cleaned this year.

  • Type your street address in the search box
  • Click on your street name and a dialog box will display the date of water main cleaning.

How We Clean

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.

Main cleaning may result in a brief period of discolored tap water for some Tri-City residents from January-June. Despite its appearance, the water will remain safe for household uses such as drinking and cooking. You should, however, minimize water use and avoid washing light-colored laundry from 7:00 a.m. to 4:00 p.m. on the day or week main cleaning is scheduled for your neighborhood.

Note: Streets adjacent to areas where main cleaning is occurring may experience discolored water as well.  

Evaluation of Recapture Options

Prior to resuming the main cleaning program this year, ACWD staff thoroughly examined possible recapture methods for the 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 the State-required processes.