Brown and Caldwell

Two engineers founded Brown and Caldwell in 1947 on a single premise: do environmental work and nothing else. The firm has held that line for nearly 80 years. Headquartered in Walnut Creek, California, it’s employee-owned, roughly 2,400 strong, and works almost entirely in water, wastewater and environmental remediation for municipal and industrial clients. Brown and Caldwell holds a program management role on Pure Water San Diego, the city’s phased potable reuse build-out. Staying single-sector is unusual at this size. Most firms that reach 2,000 people diversify into transportation or buildings to smooth the cycles, and Brown and Caldwell didn’t.

Fifty-two offices is the number that explains how a firm this narrow reaches this scale. Brown and Caldwell’s locations run across North America and into the Pacific, including Hagatna on Guam, Honolulu, Hilo and Wailuku in Hawaii, and Vancouver in British Columbia, alongside dense clusters in Florida, Ohio, Texas and Virginia. Walnut Creek anchors the California group, which also covers Sacramento, San Francisco, San Jose, Los Angeles, Irvine, San Diego and Davis.

The service list is organized around problems rather than academic disciplines: water supply and treatment, wastewater and reclamation, water resources and stormwater, site investigation and remediation, industrial water, utility performance, compliance and permitting, operations and maintenance, construction management, and program management. Two lines are newer than the firm itself, emerging contaminants and PFAS, and data center water. A proprietary optimization approach is marketed as BC:Opta, and a research and innovation group working on process intensification and water independence runs the firm’s own testing laboratory and pilot demonstration work.

On delivery, Brown and Caldwell describes three postures. It acts as owner advisor, planning and procuring collaborative delivery projects for owners who want to draw contractor interest; as design partner and engineer of record beside a contractor on design-build; or as a full-service provider from concept development through design, remediation, construction, commissioning and ongoing operations and maintenance.

The named project record backs that up. The Hyperion Advanced Water Purification Facility in Los Angeles, a 1.5 mgd plant, came through a Walsh and Brown and Caldwell design-build partnership. Big Creek Water Reclamation Facility collected several 2025 awards, including a Design-Build Institute of America National Award of Merit. Other named work includes a biosolids facility at the Blue Plains Advanced Wastewater Treatment Plant, the Lewiston water treatment plant retrofit, and the Oakley Station separation sewer project.

Safety is presented as a track record rather than a policy statement: the firm says its health and safety record and programs are recognized regularly by the National Safety Council. Leadership turned over recently, with Euan Finlay named president and chief operating officer and Stuart Henshall named chief financial officer in 2025, and in 2026 the firm entered a digital utility solutions partnership with Lantern.