Patterson Pass Water Treatment Plant Water Pipes


Investing in a strong and sustainable system

Zone 7 keeps water flowing to the Tri-Valley through an extensive distribution network that relies on both long-term capital investment projects and routine maintenance, upkeep, and prevention to keep it running smoothly. To deliver high-quality water, we have made investments in ozone treatment at both of our surface water treatment plants a priority for the Zone 7 Capital Improvement Program because ozone is the best alternative to chlorine.

We completed the Del Valle Water Treatment Plant (DVWTP) Ozonation Project in the fall of 2020, and the ozone system has been operational since that time. 

Zone 7 continued construction of ozonation treatment facilities to improve quality, taste and odor at the aging Patterson Pass Water Treatment Plant (PPWTP) this year. The project also increases the treatment plant’s production capacity from 12 to 24 million gallons per day, as well as adds clearwell storage and new filters. The project also provides for the renewal, replacement and rehabilitation of aging components of the plant. Decades in the planning, this project highlights the agency’s efforts in long-term planning, fiscal responsibility, and commitment to water quality and public health. The new facilities are largely complete and operational, with testing and remaining minor work finishing in the fall of 2022.

Significant Capital Improvement Projects

Each year, Zone 7 invests in a variety of capital improvement projects to keep our water treatment and delivery systems running optimally. Here are some of the key projects completed this year, or that are in progress, that will keep our infrastructure operating smoothly for years to come.

DVWTP Roadway/Parking Lot and Post-Ozonation Project

improving operational flexibility and plant reliability

Currently in construction, this project will replace the main parking lot and repair the access road for more efficient chemical deliveries. This project is needed to improve operational flexibility and reliability of the treatment plant and also includes modifications needed for filter backwash pumps, improvements to protect against system overflows, chemical tank repair, and a new polymer mixing system.

Mocho Groundwater Demineralization Plant Concentrate
Conditioning System

reduce the frequency of costly upkeep procedures

This project provides a sulfuric acid storage and feed system to help condition the demineralized concentrate removed from the groundwater. This helps to minimize scaling inside the discharge pipeline and reduce the frequency of costly scale removal and cleaning activities. The project is currently in construction and is expected to be complete and operational in 2023.

North Canyons HVAC System Replacement Project

sustaining Zone 7’s communications network, business operations, and public meetings

This project replaced the outdated, inefficient, and high maintenance HVAC system at Zone 7’s North Canyons office and was completed in the fall of 2022. This office is integral to Zone 7 business operations and public meetings. The office is also one of the facilities that serves as part of Zone 7’s communications network.

Chain of Lakes PFAS Treatment Project

preparing to keep your water safe for generations to come

With planning and design of the facility complete, this project is to construct a PFAS treatment facility at Zone 7’s Chain of Lakes Well No. 1 site so that all of the Chain of Lakes wells can meet regulatory requirements for operation. The treatment removes PFAS primarily through media adsorption so that groundwater from the Chain of Lakes wells is safely below current PFAS response levels and future maximum contaminant levels.

Valley Pump Station Project

increasing water system reliability during times of drought

This project was accelerated as a drought emergency project and was completed on time over the course of a year and under budget. The pump station increases Zone 7 water system reliability during times of drought and emergencies. The project increases the capacity of wells and reduces strain on pipelines by lowering operating pressure.

Financial Update

Essential Workers