Work on the $14 million 200-mgd Orinda Water Treatment Plant reliability and maintenance project consists of replacing the existing filter under drains and disinfection system and installing a redundant power building and other appurtenances and interior coating of the Orinda wash water tank. Eighty percent of the work is underground and requires full and partial plant shutdowns with provisional systems installation and other treatment plant coordination. Since the exterior of the Orinda Water Treatment Plant historical structures are not to be altered, project phasing is required to protect this historic site.