Project overview
Carter Reservoir (out of service)
These improvements will modernize our water distribution system, maintain reliable water service, and ensure continued fire flow availability.
Project objectives
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Arroyo Reservoir
- Replace aging infrastructure to extend the service life of key assets.
- Enhance operational flexibility and resiliency, ensuring reliable service during seasonal demand changes.
- Maintain fire flow capacity for emergency response readiness.
- Improve site safety by incorporating the latest safety standards at Carter Reservoir.
Understanding our water system improvements
EBMUD is making key upgrades to ensure a reliable water supply for the Moraga community. The Carter Pressure Zone relies on reservoirs and pumping plants to store and deliver water efficiently. Below is a comparison of how the water distribution system operates today and how it will improve once construction is complete.
Current water system
- Arroyo Reservoir is the only reservoir in service, holding 1.0 million gallons (MG) of water.
- Carter Reservoir has been out of service since 2011 and is not currently contributing to the system.
- Two pumping plants (Arroyo and Carter) work together to move water where it's needed, with a total pumping capacity of 1.1 million gallons per day (MGD).
- While the Carter and Arroyo Pumping Plants have a combined capacity of 1.1 MGD, Arroyo Reservoir has been the sole operational storage facility for the past 14 years.
- Despite Carter Reservoir being out of service, the water distribution system is being operated to maintain existing fire flow requirements ensuring the community remains protected.
Future water system (after project completion)
- Carter Reservoir will be rehabilitated and returned to service with a new protective coating and roof replacement, ensuring long-term reliability.
- Arroyo Reservoir will be replaced with two smaller tanks, each with a 0.29 MG capacity, for a total capacity of 0.58 MG. This will modernize the water distribution system and improve flexibility during seasonal demand changes.
- Total water storage capacity after project completion will be 0.83 MG, an optimized storage solution that balances supply and demand.
- Pumping capacity will remain at 1.1 MGD, ensuring continued water reliability and fire protection for the community.
These improvements will help EBMUD maintain a resilient water distribution system, reduce aging infrastructure issues, and ensure reliable fire flow for the community.
Project locations
- Carter Reservoir: End of Alta Mesa Drive, Moraga
- Arroyo Reservoir: End of Shannon Court, Moraga
Schedule of construction & outages
The project will be completed in multiple phases to minimize community impacts:
- April – December 2025: Carter Reservoir rehabilitation
- January 2026 – December 2027: Replacement of Arroyo Reservoir
- December 2027: Project completion
Water service will remain operational throughout the project, with hydrant flows maintained by the Carter Reservoir and Arroyo Pumping Plant. Additionally, emergency generators will be installed at Carter and Arroyo pumping plants to ensure system reliability.
Community Outreach
EBMUD is committed to keeping the Moraga community informed throughout the project. Residents will receive updates through the project webpage, email notifications, and project signs placed at key locations. To stay informed, residents are encouraged to sign up for alerts from EBMUD at ebmud.com/alerts.
EBMUD has been in communication with the Sanders Ranch Homeowners Association (HOA), where the Arroyo Reservoir is currently located, as well as the Town of Moraga and the Moraga-Orinda Fire District (MOFD) regarding project details and timelines. In the coming months, EBMUD plans to host a joint community meeting with the Town of Moraga and MOFD at Sanders Ranch to provide updates, answer questions, and address any community concerns.
Contact
Community Affairs
Email: construction-east@ebmud.com
Phone: 510-287-2053
For after-hours assistance, please contact: 1-866-403-2683