Environmental consultants in 2025 pulled through a year of shifting regulations on both federal and state levels that created uncertainty among clients.
Companies with Orange County offices recorded a 1% increase in total local billings to $538 million last year.
The Business Journal list ranks firms in Orange County based on local billings that top $10 million annually. This year’s 15 companies provide a mix of advice and assistance to a variety of organizations on environmental issues related to water pollutants, energy projects and other sustainability solutions.
“2025 ushered in uncertainties about policies and regulations, which many environmental consultants have invested large resources,” President Edward Batlle of Jacob & Hefner Associates Inc. said.
Batlle added that its clients “have been wrestling with many State versus Federal regulations” that are contradictory.
“This made it difficult for our clients to put in the capital investment needed, to provide the latest technology with more efficiency and accelerating the remediation life cycle,” he said.
Despite last year’s ups and downs, the Illinois-based company noted that clients and developers seem bullish about the next two years.
Several local firms maintained and added projects, carrying them into 2026.
A top grower in Orange County included Santa Ana-based Tait, ranked No. 6 with a 20% jump to almost $30 million in local billings.
Tait also recorded a 21% jump to $56 million in companywide billings for 2025.
No. 1 Montrose Environmental Group reported record quarterly revenues in 2025 that included local billings of $110 million from its Irvine office, up 4.8% from the year before (NYSE: MEG).
“Orange County is the place of Montrose’s founding back in 2012 and continues to be a critical and diverse market for the company, representing almost 15% of our global revenues across most of our service offerings,” Chief Financial Officer Allan Dicks told the Business Journal.
Montrose was added back to the Business Journal’s list this year with up-to-date figures and took the No. 1 spot from Pasadena-based Tetra Tech Inc., now at No. 2. Montrose reported companywide billings grew 18% to $820 million in 2025 (see story, page 20).
Fluctuating Projects and Changing Priorities
Tetra Tech recorded flat OC billings of $92 million and its companywide billings were up 3.9% to $5.4 billion (Nasdaq: TTEK).
No. 4 Aecom, with an office in Orange, reported 2025 local billings dipped 7.2% to $54 million.
The largest decrease in local billings came from No. 15 Burns & McDonnell, which dropped 70% from nearly $16 million to $4.8 million in 2025. Vice President and California General Manager Rashmi Menon attributed the fall to “the planned completion of a large project.”
“Our building activity naturally fluctuates as major projects move through their life cycles,” Menon added. “We continue to see strong demand across our markets and communities and are forecasting strong growth across the region.”
No. 5-ranked Ramboll Americas Engineering Solutions Inc., based in Arlington, Virginia, with an Irvine office, said the firm was able to survive “potential pitfalls” in the U.S. last year during a period of “shifting federal funding.”
While OC billings rose 2% to $30 million, the company reported companywide billings grew 10% to $514 million in 2025. Ramboll’s Regional Director Eric Lu said the firm has seen a boost from the technology industry.
“With the boom of data centers and increased demand for high-tech infrastructure, our experience providing data center solutions since the dot-com boom, coupled with our culture steeped in sustainability, allows us to provide clients a full range of services that fit their priorities and timeframes,” Lu said.
No. 8 Jacob & Hefner, up 4.6% to $25 million in local billings, said that new service lines such as its stormwater treatment and compliance, geoprobe, and injections division contributed to last year’s growth.
Making Headway
“The changing priorities and uncertainties in the Federal Regulations and Funding have also been a bit of a challenge, but we have been able to make headway,” Tetra Tech’s Senior Vice President Steve Tedesco said.
Tedesco said the Irvine office has added “significant PFAS projects in other Southern California Water Agencies” and is in the early phases of designing an advanced water purification facility project in the Inland Empire.
Irvine-based LSA Associates, tied for No. 12, won infrastructure, housing and energy projects last year, which led to higher revenues. The firm reported OC billings grew 10% to $16 million for 2025.
LSA added that it sees future opportunities tied to public works, housing, transportation, and energy projects in Orange County.
Research Director Desmond Celo contributed to this report.
