A major expansion is officially underway at Stanford Health Care Tri-Valley in Pleasanton, where a new three-story hospital wing is expected to more than double the capacity of the hospital’s emergency department.
The project, known as the East Wing, will add roughly 66,000 square feet to the hospital campus at 5555 W. Las Positas Blvd. Stanford Health Care Tri-Valley held a groundbreaking ceremony for the expansion in May, and construction is expected to be completed in phases beginning in 2029.
The new wing is designed to address growing demand for emergency care in the Tri-Valley. According to Stanford Medicine, emergency department visits in the region increased by almost 30% between 2013 and 2023, while emergency department capacity has not grown at the same pace.
When complete, the expansion will add 24 new patient treatment bays, three triage rooms and a larger patient waiting area. The project is also expected to include a dedicated fast-track area that can care for up to eight patients at once, helping preserve emergency beds for higher-acuity cases.
The first floor of the new building will house the expanded emergency department. The upper floors will support future inpatient growth and key hospital services, including larger spaces for the lab, pharmacy and sterile processing center.
The hospital’s Pleasanton campus spans about 27.7 acres and currently includes the main hospital building, medical offices and a central utility plant. As part of the expansion, crews will also reconfigure the campus loop road, adjust surface parking, relocate utilities and add infrastructure intended to support hospital operations in the event of a major earthquake or disaster.
Pleasanton city materials show the project was approved through the city’s design review process before construction began. The Pleasanton Planning Commission unanimously approved the expansion plan in 2025.
The project is also a major financial investment. Pleasanton Weekly reported the scope includes a three-story, $200 million building, along with new utilities, roads and parking.
Stanford Health Care Tri-Valley is the former ValleyCare system, which became part of Stanford Health Care in 2015. Hospital officials have framed the new wing as both a response to the Tri-Valley’s population growth and a way to keep more emergency care close to home.
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