Yosemite National Park broke ground on July 24, 2025, on the new El Portal Wastewater Treatment Plant, a $239 million investment funded through the Great American Outdoors Act's Legacy Restoration Fund.
The 45-year-old treatment plant is the National Park Service's (NPS) largest such facility and serves as the sole wastewater treatment system for Yosemite Valley, El Portal and nearby communities. It supports more than 4 million annual visitors, 700 residents and hundreds of park and partner employees.
The project aligns with recent executive and secretary's orders to invest in the infrastructure of national parks and improve services to ensure national parks remain open and accessible for the benefit and enjoyment of the public.
"This project is essential to the continued protection of public health and the environment, and also to the future of visitor services and park operations in Yosemite," said Ray McPadden acting superintendent. "Upgrading this facility allows us to better safeguard the Wild and Scenic Merced River, serve our community and guests, support park concession operations and ensure the park remains resilient for the next 50 years."
The modernized plant will treat up to 1 million gal. of wastewater per day, incorporating advanced treatment technologies, improved system redundancy and upgraded automation controls.
In addition to the core plant upgrades, the project includes the demolition of outdated structures and the rehabilitation of the former El Portal administrative camp to house construction crews in RV sites, minimizing housing costs and environmental impact during the project.
The outdated system is deteriorating and provides insufficient treatment capacity. Replacement components are difficult to procure or no longer manufactured due to the age of the existing plant increasing the likelihood of environmental damage and incurring costly emergency repairs.
Once completed, the new plant will not only meet today's regulatory and environmental standards but also enhance operational reliability and reduce future maintenance costs.
The project, scheduled for completion in 2029, is expected to address approximately $156 million in deferred maintenance and repair needs across the wastewater system infrastructure.
Construction is being carried out through a design-bid-build strategy under the direction of the NPS Denver Service Center, in coordination with the Pacific West Region and Yosemite National Park staff.
