In April, Bowman Consulting expanded its mining services through the acquisition of Arizona-based PLS Group. In July, it joined forces with leading land development consultant JMH Weiss, opening an office in San Jose, Calif., its 18th office nationwide.

In October, the company was added to The Zweig Letter 2012 Hot Firm List as one of the 100 fastest-growing architecture, engineering, planning and environmental consulting firms in the United States and Canada. And it continued its expansion, absorbing key members of the former McDonough Associates in December and opening an office in downtown Chicago to enhance its presence in the transportation sector. Just a few weeks ago, Bowman acquired Austin, Texas-based Loomis Partners, an established engineering and surveying firm whose environmental group is widely recognized for its habitat conservation planning projects.

The company describes itself as “dynamic, progressive and diversified” and touts its “leading edge technical expertise” and “in-depth knowledge of local building and development regulations.” But there is something more fundamental driving the success of the Chantilly, Va.-based firm. In a word, it’s all about relationships.

“Having turnkey solutions and services isn’t enough,” said James Hall, VP of Bowman Consulting. “You have to be truly passionate about the city you are working in, help them grow by bringing in local jobs, have top environmental standards and really walk the walk. This is infectious to clients, prospects and top talent who want to work for your firm.”

Case in point: Bowman’s partnership with Pittsburgh-based Gateway Engineers, which began in August 2011 as a way to position the two firms as the premiere service provider to the area’s oil and gas market. Bowman opened an office near Gateway’s headquarters, hiring dozens of local environmental specialists, licensed surveyors, engineers and pipeline design professionals.

The agreement enabled Gateway—already well-connected in the area—to expand its resources and capacity, while allowing Bowman entry into a new markets and an established client base.

“The premise of our growth has been relationships,” said Hall. “Even before the recession hit, we didn’t want to be complacent and consider ourselves just a residential and commercial firm. We looked at what we didn’t have and assessed the gaps. When we opened the office in Pittsburgh, for example, we looked at other services that would set us apart. We didn’t have pipeline design at that time and bringing that in was a real game changer in the oil and gas industry. A lot of our clients have that service internally but are at capacity and need to outsource that piece.”

“A lot of the offices we have grown across the country are based on years of relationships,” he added. “We are always looking at ways to bring our services together and help each other be successful by leveraging each other’s resources.”

This is also true for the firm’s most recent expansion into central Texas. As projects in the power and energy arena began pulling Bowman into Texas, the firm saw an opportunity to partner with Austin-based Loomis Partners.

“Power and energy are definitely a strong strategic growth area for the firm,” said Hall. “We provide excellent service, and that moves into other industries. Clients want the service they got at Bowman, so we go in, get local support, and couple that with leadership and relationships in the firm that can support that area.”

Bowman plans to continue its expansion in 2013, relying on the diversity of its services and the talent of its people to identify and pursue new market opportunities. Technical expertise will remain fundamental to the firm. But Hall’s focus is broader.

“On a human level, it’s pretty simple what makes people successful,” he said. “We are in the industry of helping people help others, and the trick is not to have an ego about it. In many cases, we will team with competitors because it makes the most sense for the client. We know that in the long term, if we take care of the client, we will succeed.”