Willdan History Timeline

Willdan was created in 1964 by two engineers who shared a vision of solving the challenges larger communities face. That two-person crew would grow into a national team of 1,600+ professionals. Today, we are not only recognized for our vast engineering experience, but also for our innovative energy work and trusted technical expertise.

City Report

Founding Mission

Willdan is founded to help plan and guide the urbanization of Dairy Valley, now the City of Cerritos in Los Angeles County, California.


William Stookey and Dan Heil form a partnership, opening their first office in a trailer in a cow field behind City Hall, to work with Dairy Valley providing building and safety, contract staff support, and civil planning and engineering services.

This mission of serving public agencies with contract engineering and planning would guide the fledgling company over the next decades.

Paramount Civic Center

Start of 50+ Years with Paramount

The City of Paramount contracts with Willdan for City Engineering services. This contract represents Willdan’s longest continuous client relationship — more than 50 years. In this time, Paramount is transformed and named the “All-American City.”

1970 - 1990
I805 under construction

Expansion: Bridge and Disaster Recovery

Over the next two decades, Willdan grows its civil and structural engineering, disaster recovery and districting services, and expands throughout the Southwest.

Willdan designs seismic retrofits of bridges
state-wide for the California Department of Transportation in response to the collapse of freeway overpasses due to regional quakes.

John Knipe, Contract City Engineer at Westlake Village for 20+ years, reports on Lindero Canyon Road Bridge

City of Westlake Village

Willdan is awarded an ongoing contract to provide city engineering services to the City of Westlake Village in Ventura County, California. Willdan has overseen over 500+ City projects to date, garnering awards such as Transportation Project of the Year for Lindero Canyon Road Bridge.

Aerial view of LA River Channel

LA River Flood Control

Willdan begins providing civil, structural, geotechnical engineering, and management services to the Los Angeles River Flood Control project for the U.S. Army Corps of Engineers. This project is later awarded APWA’s National Project of 2002 and has saved residents in 14 communities millions of dollars in flood insurance to date.

public finance experience map

Addition: Public Finance Consulting

Willdan acquires MuniFinancial, one of the largest public finance consulting firms in the U.S., based in Temecula, California. Willdan opens an Orlando, Florida office which continues to serve public finance clients in the Southeast. Over the next two decades, Willdan extends public finance consulting services to most U.S. states.

training exercise

Addition: Emergency Preparedness Solutions

In response to new client needs after the attacks on September 11, 2001, Willdan develops Homeland Security services to provide emergency response, hazard planning, analysis, training, and community and enterprise resilience to meet clients’ greatest emergency preparedness challenges.


Initial Public Offering (IPO)

Willdan Group, Inc. completes initial public offerings in NASDAQ, becoming a publicly traded company under the symbol WLDN. This generates an infusion of resources to enable the company to expand into new areas and raise funds for future growth.

Tom Brisbin

New CEO: Tom Brisbin

Tom Brisbin joins Willdan as CEO. Formerly a top executive at AECOM and TetraTech, Tom brings strategy for bold growth and a forward-looking orientation.

Energy efficiency installs at Hilton

Addition: Energy Solutions

Willdan adds energy efficiency (EE) to its solutions with the acquisition of Intergy Corp. This California-based consulting firm has assisted companies, institutions, and agencies with planning and implementing their EE, water conservation, and renewable energy strategies with proprietary software, since 2003.

Our ConEd Green Team installer

Expansion: New York

Willdan wins Consolidated Edison’s Small Business Direct Install Program for EE upgrades. Willdan opens a Manhattan office and goes on to win contracts with the New York State Energy Research & Development Authority (NYSERDA), the New York Power Authority (NYPA), and the NYC Energy Efficiency Corporation (NYCEEC). Through these services, Willdan helps New York State work toward its goal to reduce statewide energy usage.

Elk Grove Rain Garden

Elk Grove Public Works Department

The City of Elk Grove, California contracts with Willdan to staff an entire Public Works Department. Willdan-managed projects garner multiple awards, especially for California’s most comprehensive Rain Garden and city-wide streetlight LED replacements.

PSE installers

Expansion: New Regions

Willdan opens offices in Illinois, Texas, New Jersey, Washington DC, Washington State, and elsewhere. Willdan’s intrepid direct install team crisscrosses Washington State from 2015 to present, creating a buzz in towns of all sizes for Puget Sound Energy (PSE) EE initiatives.

Willdan PM monitors air quality

Addition: Performance Contracting, Building Engineering

Willdan expands into performance contracting and building energy engineering by acquiring 360 Energy Engineers and Abacus Resource Management Company. 360 is a leading engineering and energy management consulting firm based in Lawrence, Kansas. Abacus serves utility and municipal clients in the Pacific Northwest. Above: Willdan monitors an air quality control project at King County Aquatic Center, WA.

Community microgrid report

Community Microgrids

NYSERDA selects Willdan to analyze the feasibility of constructing community microgrids in eight New York communities. Willdan’s successful performance on this project leads to microgrid projects in other states.

Marshak Science Towers energy efficient install

Addition: Power Engineering, DER Capabilities

Willdan acquires Genesys Engineering, P.C., a power engineering firm in New York, bringing strong expertise in large-scale university and industrial energy infrastructure, specifically cogeneration and central plant engineering. This acquisition strengthens Willdan’s capabilities in distributed energy resources (DERs).

Integral Analytics booth

Addition: Big Data Analytics Software

Willdan acquires data science firm Integral Analytics (IA). As a recognized leader in big data analytics software, IA helps utility managers evaluate and dispatch electricity resources more effectively as the electric grid transforms and incorporates DERs. This acquisition strengthens Willdan’s capabilities in grid data analytics.

Willdan - NAM

Addition: Bay Area Energy Engineering

Willdan acquires Newcomb Anderson McCormick (NAM), an energy engineering consultancy with 13 years of expertise in EE projects, DERs, and strategic energy plans and programs primarily for municipal and higher education customers, especially in the Bay Area of California.

Willdan-Lime Energy

Addition: Mid-Atlantic and Southeastern EE Direct Install Programs

Willdan acquires Lime Energy Co., which has designed and implemented direct install EE programs for 15 of the largest utilities in the U.S. The acquisition expands Willdan’s customer base and its geographical presence in southeastern and mid-Atlantic regions.

Willdan-The Weidt Group locations map

Addition: Energy Performance Software for New Buildings

Willdan acquires The Weidt Group, an energy consulting and software development firm that has specialized in energy and operational performance of new and existing buildings since 1977. This acquisition also expands Willdan’s geographic footprint.


Addition: Industrial Energy Efficiency

Willdan acquires Onsite Energy Corp., which has specialized in industrial energy management services in California since 1982.


Addition: Energy Analysis and Strategy

Willdan acquires Energy and Environmental Economics, Inc. (E3), developers of industry-leading analytical tools in electrical resource planning, GHG scenarios, and energy markets analysis since 1989.

Key Implementer for New CA IOU EE Programs

Key Implementer for New CA IOU EE Programs

Willdan is awarded eight new energy efficiency programs statewide for four California Investor-Owned Utilities (IOUs): Southern California Edison (SCE), San Diego Gas & Electric (SDG&E), Pacific Gas & Electric (PG&E), and Southern California Gas Company (SoCal Gas).

Inaugural Sustainability Report

Inaugural Sustainability Report

Willdan is committed to environmental stewardship; the health, welfare, and development of employees; and supporting local communities. This Sustainability Report demonstrates Willdan’s commitment to these values by tracking and reporting environmental, social, and governance (ESG) performance.

Decarbonization with NYCHA Public Housing

Decarbonization with NYCHA Public Housing

Willdan is working with the New York City Housing Authority (NYCHA) to meet Local Law 97 (LL97) mandates and provide innovative, eco-friendly technology to reduce GHG emissions. This is one of the largest public housing decarbonization projects in the nation.

LL97 Implementation Action Plan for NYC

LL97 Implementation Action Plan for NYC

Willdan uses in-house software (B3 Benchmarking and NEO Net Energy Optimizer®) to remotely model and evaluate 4,000+ NYC buildings. Based on these results, Willdan creates an LL97 Implementation Action Plan with practical strategies to reduce NYC Government’s CO2 emissions 40% by 2025 and 50% by 2030.

Decarbonization Plan for the 5 National Parks

Decarbonization Plan for 5 National Parks

Willdan develops an investment plan for each of the five national parks of Lake Superior to achieve a 100% GHG emissions reduction in land-based operations by eliminating fossil fuel use and switching to renewable electricity.

Provides Planning Software to One of the Largest U.S. Utilities

Provides Planning Software to One of the Largest U.S. Utilities

One of the nation's largest energy delivery companies and their operating companies have licensed Integral Analytics (Willdan’s wholly owned software subsidiary) LoadSEER software to evaluate integrated grid-planning alternatives.

New CEO: Mike Bieber

New CEO: Mike Bieber

Mike Bieber is named as CEO, succeeding Tom Brisbin. Mike has served as Willdan’s President for the last seven years. He possesses vast experience in both organic and acquisitive growth, and overall company operations, along with a proven track record of solving world-class problems.

EE for Nations 5th Largest School District

EE for Nation’s 5th Largest School District

Willdan is selected by Clark County School District — the fifth-largest in the U.S. — to design, implement, and maintain advanced lighting and controls upgrades. The resulting EE projects are expected to transform Nevada’s learning environment over the next 10 years.

60th Anniversary

60th Anniversary (May 28, 2024)

Willdan has grown from 2 founding engineers in 1964 to 1,600+ employees across 53 offices and 25 states nationwide. These employees share a vision of transitioning communities to a clean energy and a sustainable future.

Today: Now in our second half century, we continue our core mission of serving communities with superior technical solutions, along with a comprehensive suite of services and software to meet current and future challenges and opportunities.