Santa Monica Upgrades Water Treatment Infrastructure

The city finished an expansion of the Arcadia Water Treatment Plant in August 2025 to increase local water supply.

Updated on Oct. 26, 2026 in Utilities

Santa Monica Upgrades Water Treatment Infrastructure

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Should local governments prioritize infrastructure upgrades to increase your community's local water autonomy?

Completed in August 2025, Santa Monica finalized the $77.5 million restoration of the Olympic Well Field and the expansion of the Arcadia Water Treatment Plant. This project successfully boosts the city's local drinking water production capacity while improving overall facility efficiency.

Why it matters

The initiative supports Santa Monica's goal of sourcing 70% of its total drinking water from local supplies. By increasing efficiency and capacity, the city aims to bolster its resilience and reduce dependence on outside water sources.

The $77.5 million project saves nearly 1,200 acre-feet of water annually while increasing reverse osmosis recovery rates to over 90%. Additionally, the plant now operates at a lower energy intensity of 0.287 kilowatt-hour per cubic meter.

The players

Arcadia Water Treatment Plant

This is a municipal facility in Santa Monica that processes local groundwater to provide safe drinking water for city residents.

Olympic Well Field

This critical piece of local infrastructure provides the raw groundwater supply that is treated at the neighboring Arcadia facility.

The details

The facility employs flow-reversal technology, which periodically switches the direction of feed flow through membrane pressure vessels to maintain performance. This retrofit involved installing 56 valves per reverse osmosis train and incorporates advanced treatment methods like ultraviolet light with hydrogen peroxide.

Project construction was completed in August 2025.

Market Landscape

This facility expansion aligns with the California Urban Water Management Plan requirements for cities to increase drought resiliency. It signals a shift toward higher-efficiency water recovery technology as urban centers compete for stable, local resource control.

Residents benefit from a more stable and resilient local water supply that reduces reliance on imported water. Furthermore, the $250,000 in combined annual operational savings on maintenance and chemicals helps optimize the city's utility budget.

The takeaway

Cities investing in advanced membrane technologies can significantly reduce the energy and maintenance costs required to treat groundwater. These upgrades provide a long-term strategy for maintaining a consistent water supply in drought-prone regions.