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ALERT: Calaveras Road Closure Extended to September 30, 2018.
Calaversas Road Closure map
  • See a map of the closure.
  • What:

    The Closure of Calaveras Road to thru traffic between Milpitas and Sunol has been extended to September 30, 2018.

    The road had also been closed on weekends and holidays because of a land slide that undermined the road within the closure section. Please keep checking back for schedule details.

    This is due to storm damage along this stretch of road. Under normal conditions and the construction schedule, Calaveras Road would be open to thru traffic on weekends and holidays. However, this is no longer the case, and the road will remain closed every day to all traffic until further notice. 
    Please avoid this area and use alternative routes.



    The heavy winter rains in early 2017 and the subsequent landslide that undermined a portion of Calaveras Road (which is the primary access to the construction site) have caused a significant delay in the construction of the dam. The contractor is months behind schedule due to the inability to haul materials for construction of the dam on Calaveras Road.

    Therefore, we have received permission from Alameda County to extend the closure by nine months to September 30, 2018.

    A new road has been cut into the hillside to bypass the undermined portion. That new section of road will become a public roadway starting sometime in 2018 at which time it will be reopened on weekends and holidays. For now the road is closed to all through traffic every day of the week.

    The San Francisco Public Utilities Commission (SFPUC), owner and operator of the Hetch Hetchy Regional Water System, is building a new dam to replace the existing 91-year-old Dam at Calaveras Reservoir in the Sunol Valley. Restoring Calaveras Reservoir is one of the most important projects of the $4.8 billion Water System Improvement Program. Calaveras Reservoir is the Hetch Hetchy Regional Water System’s largest Bay Area reservoir when it is full. Restoring its historic levels is crucial for water supply in times of drought and emergencies. Construction on the earth and rock fill dam began in 2011.

    Although 85 percent of the materials for the new dam will come from on-site, approximately 300,000 cubic yards of sands and gravels and 150,000 cubic yards of hard rock will need to be imported to the site for construction of the dam. These materials will be imported in large hauling trucks on Calaveras Road between Highway I- 680 in Sunol and the Calaveras Dam entrance (at Oakridge Road). At its peak, truck traffic could amount to one haul truck every 5 minutes on Calaveras Road during heavy hauling activities.


    It is not safe for this many large trucks to share the narrow portions of Calaveras Road with cyclists and private vehicles.

    Therefore, we have worked with Alameda and Santa Clara Counties to close this portion of Calaveras Road to cyclists and private vehicles while we are hauling on weekdays.

    Road Closure Details
    • Where: Calaveras Road just south of Geary Road (entrance to Sunol Regional Wilderness) to Oakridge Road – near the Alameda / Santa Clara County line.
    • When: from July, 2016 to September 30, 2018. The Road will be open on weekends and holidays starting sometime in 2018. Please check back for future updates.
    The portion of Calaveras Road just south of Geary Road (location of entrance to Sunol Regional Wilderness) to Oakridge Road – near the Alameda/Santa Clara County line.

    We sincerely apologize for any inconvenience this may cause you and greatly appreciate your patience and support as we upgrade the regional water system.
    If you have any further questions, feel free to call our toll-free 24 hour answer line at (866) 973-1476.

    Email or


    Learn more about the Calaveras Dam Replacement Project here.


    Last updated: 8/30/2018 1:05:11 PM