Orinda Water Treatment Plant Disinfection Improvements Project

 Orinda WTP Disinfection Improvements Project Final Supplemental EIR

Orinda WTP Disinfection Improvements Project Final Supplemental EIR Volume III is available below in the documents section and includes the Draft Supplemental EIR Volumes I and II. 

Orinda Water Treatment Plant Disinfection Improvements Project560_Orinda_WTP_Disinfection_Improvements_Map_FINAL.png

As part of EBMUD’s Water Treatment and Transmission Improvements Program (WTTIP), EBMUD is upgrading and replacing existing facilities and constructing new facilities at the Orinda Water Treatment Plant (WTP), located at 190 Camino Pablo in the City of Orinda, California. Built in 1935, Orinda WTP is the heart of the EBMUD water distribution system, delivering water to more than 800,000 customers every day, including customers in the City of Orinda.

The Orinda WTP Disinfection Improvements Project (Project) will improve current water treatment processes by adding ultraviolet (UV) disinfection and a chlorine contact basin. Adding these disinfection improvements will reduce the formation of disinfection byproducts which form when chlorine reacts with naturally-occurring organic matter in water. The Project will provide reliable water treatment infrastructure that meets long-term operational needs and will continue to meet drinking water and environmental regulations to achieve EBMUD’s internal long-term water quality goals. The Project includes demolition of an existing maintenance building and construction of a new disinfection facility comprised of a new above-ground two-story maintenance and UV electrical (MAUVE) building with a below-grade UV structure and a below-grade chlorine contact basin (CCB), two electrical buildings, a standby generator, pipelines and vaults, and other supporting facilities. The MAUVE building with UV structure and the CCB would be adjacent and fully integrated facilities. Maintenance activities and associated uses previously housed in the existing maintenance building that will be demolished will be incorporated into the Project disinfection facility and grounds maintenance building with associated parking at the Orinda WTP site. The Project will also remove vegetation, install landscaping, replace existing and install new security fencing, and restore the site following construction.

Construction is expected to occur over a four and a half-year period from 2021-2025.

Workplan and Schedule

The Project is a modification of the disinfection improvements that were analyzed in EBMUD’s WTTIP Environmental Impact Report (EIR), which was certified in 2006. EBMUD prepared a Supplemental EIR for the Project.

The overall workplan and schedule is as follows:

  • Notice of Preparation (NOP) of Supplemental EIR Publication – August 15, 2019
  • NOP Scoping Meeting #1 – August 26, 2019 at Masonic Lodge, 9 Altarinda Road, Orinda
  • Landscape Review Public Meeting #2 – October 21, 2019, 7:00p.m., Orinda Masonic Lodge, 9 Altarinda Road, Orinda
  • Virtual Community Meeting #3- May 13, 2020 6:00p.m. Presentation Recording: https://youtu.be/cdGDm75Ilbw
  • Draft Supplemental EIR Publication – July 24, 2020
  • Public Meeting to Review Draft Supplemental EIR – August 20, 2020
  • Virtual Community Meeting #4- August 20, 2020 6:00p.m. Presentation Recording: https://youtu.be/h5vATykpQpo
  • Final Supplemental EIR Publication – November 20, 2020
  • EBMUD Board Consideration of Final Supplemental EIR – December 8, 2020

For project specific questions or comments contact: 


For other inquires, contact:

Community Affairs 
Email: Kathryn.Horn@ebmud.com
Phone: 510-287-2053

Contractors: For bid opportunities please see the Business Center

EBMUD WTTIP EIR (2006) – for reference only