Plant Profile: North Pleasant Valley Groundwater Desalter Plant

Feb. 25, 2022

New desalter plant doubles water supply production from local groundwater sources

About the author:

Carol Brzozowski is a freelance writer for Water & Wastes Digest. Brzozowski can be reached at [email protected].

Location: Camarillo, California

Size: Treats 4,500 acre feet per year; yields 3,800 acre feet per year

Equipment: greensand filters, reverse osmosis, monitoring, pumps

For nearly two decades, groundwater quality in the northern portion of the Pleasant Valley Groundwater Basin in Ventura County, California, continuously declined due primarily to the infiltration of poor-quality surface water.

These challenges were a driving factor in the city of Camarillo reducing groundwater pumping and increasing the blending of imported water with Wells A and B, two of Camarillo’s largest wells.

Imported water comprised up to 60% of Camarillo’s water supply, with the remaining 40% coming from local groundwater.

After deciding to mitigate those challenges to the water supply, water quality, local economy and the watershed, the city completed in the winter of early 2018 a revised supplemental environmental impact report, initiating construction of the North Pleasant Valley (NPV) Groundwater Desalter Plant in 2019.

Project Goals & Stakeholders

This project is an immediate water supply solution with many benefits on a local and regional scale. This project creates a new water source, protects the groundwater basin that the region depends on, and supports the agricultural economy.

The NPV Groundwater Desalter Plant reduces dependence on imported water by using greensand filtration and reverse osmosis (RO) to treat salty groundwater and create high-quality drinking water.

Camarillo recently commissioned the $66.3 million plant. The new desalter facility is designed by Brown and Caldwell and constructed by W.M. Lyles Co. RO design was provided by design project team Separation Processes. Platt/Whitelaw Architects provided sustainable facility architectural design and energy efficiency expertise.

The new desalter plant doubles water supply production from local groundwater sources, reducing the dependence on imported water and saving customers an estimated $43 million over the next 20 years.

The initial phase of the desalter plant can treat 4,500 acre-feet per year (AFY) of salty groundwater from the Calleguas Creek watershed. Treatment will yield up to 3,800 AFY of high-quality drinking water using greensand filtration and RO technologies to double the city’s local potable water supply.

The greensand filters will remove naturally occurring iron and manganese. The RO water purification process uses a semi-permeable membrane to filter out unwanted dissolved molecules, contaminants, and other parameters such as chlorine and salt from drinking water. RO cleans water down to a molecular level, leaving only pure water behind.

The desalter project infrastructure includes nine monitoring wells at three locations, connection to Calleguas Municipal Water District’s Salinity Management Pipeline, and conveyance pipelines to connect the refurbished Wells A and B to the treatment site and transport treated water to the city’s system.

Salty groundwater from the North Pleasant Valley Basin will be pumped from two existing wells via a new pipeline to the NPV Desalter Facility. Brine from the RO treatment process will be discharged through an existing brine pipeline and outfall in
Port Hueneme.

The projected 11 million tons of salt removed from the watershed annually will be sent to the Pacific Ocean via an existing ocean outfall, which is designed to aid state, federal, and local stakeholders in meeting regulations to protect the Calleguas Creek watershed’s long-term health

Economic Boom

By creating a new water source for the community, the North Peasant Valley Desalter Facility is a critical water supply project for the city of Camarillo that also  benefits the watershed and the economy.

The city of Camarillo depends on groundwater from the Pleasant Valley Groundwater Basin not only to supply potable water to the area’s residential population, but its business and agricultural communities as well.

In the project’s protection of the basin to benefit the regional economy, it mitigates a situation in which over the past two decades, water levels in the northern portion of the Pleasant Valley Groundwater Basin have risen more than 200 feet.

At the same time, the accumulation of salts through infiltration of surface water from the Arroyo Las Posas has degraded the quality of water, resulting in a large mound of poor quality groundwater, putting the area’s agricultural and supporting business communities at risk.

The project also increases recycled water quality to benefit the agricultural community and the ecosystem.

Economic benefits are derived in that agriculture and businesses that support agriculture provide an estimated 43,000 jobs in the area. By removing salts from the basin and reducing basin degradation, the project helps preserve this prime economy in the region.

The project also serves a purpose in enhancing the beneficial uses of the watershed. The project will remove 11 million tons of salts each year from the watershed, helping state, federal, and local stakeholders meet a regional Total Maximum Daily Load (TMDL) to guarantee the long-term health of the watershed.

Solving Impaired Groundwater

The project is a key part of the regional solution to address impaired groundwater in the basin by preventing the salt plume from spreading to the main portion of the Pleasant Valley Basin.

In terms of water supply, by 2035, the city was expected to import 70% of its water supply from the State Water Project (SWP). This project will provide reliable, drought-resistant potable water and reduce imported water to 25% of the city’s water supply.

Reducing imports from the SWP will enhance the Sacramento Bay Delta ecosystem through reduced diversions and increase habitat for endangered species.

Brown and Caldwell Project Manager Andrew Lazenby notes the project is a landmark moment for Camarillo’s long-term water future.


“We applaud the city’s visionary approach to reclaiming and reusing groundwater and doing so in a way that is both cost-effective for customers and beneficial to the environment,” Lazenby said.

Speaking to the project’s immediate water supply solution enabling many local and regional benefits, Dave Klotzle, Camarillo director of public works, said: “This once-in-a-generation project creates an affordable, drought-resistant potable water supply while serving an estimated 43,000 people within the city’s water service area. By removing salts from the Pleasant Valley Groundwater Basin and reducing basin degradation, the project helps preserve this natural resource in the region.”

In addition to the modernization of the infrastructure with new pipelines, pretreatment filtration system support facilities and three new monitoring wells, there also are provisions for future solar power installation.

The North Pleasant Valley Groundwater Desalter Plant has been configured to include educational elements, including tours, informational signage, and learning opportunities for students and the public.

About the Author

Carol Brzozowski

Carol Brzozowski is a freelance writer for Wastewater Digest. Brzozowski can be reached at [email protected].