Overview
Starting in February 2026, EBMUD will temporarily drain Central Reservoir as part of a multi-year project to modernize water storage at the site. Central Reservoir is the largest distribution reservoir in EBMUD’s system and plays a key role in delivering drinking water to Oakland, Alameda, San Leandro, San Lorenzo, Berkeley, and Emeryville.
Originally built in 1920 and reconstructed in 1961, Central Reservoir can store up to 154 million gallons of water—about 18% of EBMUD’s total distribution storage. The reservoir is an open-cut reservoir, meaning it is an earthen basin lined and covered to hold treated drinking water.
Over the next several years, Central Reservoir will be taken out of service each winter so EBMUD can safely test the system and prepare for construction of new water storage facilities.
Why Are We Doing This?
EBMUD is planning to replace Central Reservoir with three modern concrete water storage tanks, each holding 14 million gallons. These improvements will:
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Improve drinking water quality by reducing how long water sits in storage before reaching customers
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Better protect drinking water from environmental contamination
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Reduce earthquake risk by replacing an older earthen structure with modern seismic-resistant tanks
Taking the reservoir offline each winter allows EBMUD to confirm that the water system can continue to operate reliably without Central Reservoir before permanent construction begins.
Community Benefits
This project provides long-term benefits to the community, including:
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Safer, higher-quality drinking water
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More resilient infrastructure that performs better during earthquakes
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Improved environmental protection through modern tank design
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Reliable water service maintained throughout construction
During the drainage, EBMUD will closely monitor Sausal Creek to protect public safety and the environment.
What Will Happen During the Drainage
After Central Reservoir is disconnected from the water distribution system, the remaining water will be released in a controlled manner into Sausal Creek. This will typically occur in mid-February.
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Creek flows will be temporarily higher than normal
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The increased flow will be similar to what the creek experiences during a moderate winter rainstorm
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Elevated flows will extend from East 27th Street in Oakland downstream to the bay
EBMUD’s Fisheries, Water Quality, and Regulatory teams will monitor the operation to ensure environmental and safety standards are met. A similar discharge occurred in March 2023 during an emergency response to water quality concerns. At that time, water was released at a rate of 110 cubic feet per second, and no adverse environmental impacts were observed.
Timeline
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Winter (annually, starting 2026): Central Reservoir taken out of service for testing
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Mid-February (each year): Controlled drainage into Sausal Creek
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Following years: Continued testing and preparation for construction
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Future phase: Construction of three new concrete water storage tanks
Related Projects
Central Reservoir Replacement Project
Contact
Community Affairs
Email: construction-south@ebmud.com
Phone: 510-287-0544
For after-hours assistance, please contact: 1-866-403-2683
Contractors: For bid opportunities on EBMUD projects, see Business Center.