Company lists · Data refreshed September 2026

Top 25 Environmental engineering firms based in the United States

Name: Environmental engineering firms based in the United States
Creator: RevenueBase
License: https://creativecommons.org/licenses/by/4.0/

Compiled by the RevenueBase Data Team Data refreshed Sep 16, 2026 6,932 companies tracked

RevenueBase identified 6,932 company matches for environmental engineering firms associated with the United States as of September 2026 and tracks 310,384 professional contacts across them, including 149,573 with verified work emails. Houston is the largest hub.

This list covers company matches for environmental engineering firms associated with the United States, found by RevenueBase SmartSearch using the meaning of business descriptions in its company graph at Exact. Ranked by professionals tracked, largest first. Rows show recorded descriptions where available, Exact search membership and the snapshot date. Data refreshed September 16, 2026.

Published by RevenueBase, a B2B data infrastructure company. This list was built with RevenueBase SmartSearch, the natural-language company search RevenueBase customers use to build their own targeted lists and unlock verified emails and direct dials at the companies on them. How these lists are built and judged.

How to read this list RevenueBase SmartSearch · Exact Recorded Sep 16, 2026 How this list was built

6,932Companies

310,384Contacts tracked

149,573Verified emails

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The 25 largest environmental engineering firms based in the United States

Ranked by team size

Top 25 of 6,932 company matches for environmental engineering firms based in the United States, ordered by professional contacts tracked in RevenueBase, largest first. Recorded Sep 16, 2026. The RevenueBase SmartSearch column shows Exact match membership in this saved search. Click a contact count to view that company's people. Totals use company locations recorded by RevenueBase; the displayed preview is a smaller selection.
#	Company	RevenueBase SmartSearch	Headquarters	Employees	Contacts
1	Tetra Tech	Exact match	Pasadena, CA, United StatesHQ recorded Sep 16, 2026	10001+	12,999 contacts →
	Exact match “Tetra Tech is the leader in water, environment and sustainable infrastructure, providing high-end technical and engineering services for projects worldwide.” Recorded in the RevenueBase company graph · Sep 16, 2026 · View company records in RevenueBase
2	WSP In The U.S	Exact match	New York, NY, United StatesHQ recorded Sep 16, 2026	10001+	9,318 contacts →
	Exact match “What if you could shape built and natural environments – and the future of those that use them?” Recorded in the RevenueBase company graph · Sep 16, 2026 · View company records in RevenueBase
3	Clean Harbors	Exact match	Norwell, MA, United StatesHQ recorded Sep 16, 2026	10001+	8,924 contacts →
	Exact match “Clean Harbors is North America’s leading provider of environmental and industrial services.” Recorded in the RevenueBase company graph · Sep 16, 2026 · View company records in RevenueBase
4	CDM Smith	Exact match	Boston, MA, United StatesHQ recorded Sep 16, 2026	5,001-10,000	7,527 contacts →
	Exact match “CDM Smith is shaping what’s next, now, with world class solutions in water, environment, transportation and energy to public and private clients worldwide.” Recorded in the RevenueBase company graph · Sep 16, 2026 · View company records in RevenueBase
5	Terracon	Exact match	Olathe, KS, United StatesHQ recorded Sep 16, 2026	5,001-10,000	6,113 contacts →
	Exact match “Terracon is a 100 percent employee-owned consulting engineering firm providing quality services to clients.” Recorded in the RevenueBase company graph · Sep 16, 2026 · View company records in RevenueBase
6	Michael Baker International	Exact match	Pittsburgh, PA, United StatesHQ recorded Sep 16, 2026	5,001-10,000	4,362 contacts →
	Exact match “Michael Baker International is a leading provider of engineering, consulting, and technology services spanning four Verticals: Infrastructure, Places and Facilities, Federal and…” Recorded in the RevenueBase company graph · Sep 16, 2026 · View company records in RevenueBase
7	APTIM	Exact match	Baton Rouge, LA, United StatesHQ recorded Sep 16, 2026	1,001-5,000	2,639 contacts →
	Exact match “APTIM enhances the quality of the environment, wellbeing of people, resilience of communities, and opportunity for employees to make a difference, not just a living.” Recorded in the RevenueBase company graph · Sep 16, 2026 · View company records in RevenueBase
8	Brown And Caldwell	Exact match	Walnut Creek, CA, United StatesHQ recorded Sep 16, 2026	1,001-5,000	2,473 contacts →
	Exact match “Headquartered in Walnut Creek, Calif, Brown and Caldwell is an employee-owned firm with 2,100+ professionals serving clients locally and globally from 52 locations.” Recorded in the RevenueBase company graph · Sep 16, 2026 · View company records in RevenueBase
9	Geosyntec Consultants	Exact match	Boca Raton, FL, United StatesHQ recorded Sep 16, 2026	1,001-5,000	2,393 contacts →
	Exact match “Geosyntec is a consulting and engineering firm that works with private and public sector clients to address new ventures and complex problems involving our environment, natural…” Recorded in the RevenueBase company graph · Sep 16, 2026 · View company records in RevenueBase
10	Providence	Exact match	Baton Rouge, LA, United StatesHQ recorded Sep 16, 2026	n/a	2,232 contacts →
	Exact match “Providence is an employee-owned engineering and environmental consulting firm.” Recorded in the RevenueBase company graph · Sep 16, 2026 · View company records in RevenueBase
11	ECS Group Of Companies	Exact match	Chantilly, VA, United StatesHQ recorded Sep 16, 2026	1,001-5,000	2,210 contacts →
	Exact match “ECS Group of Companies is a Chantilly, VA-based consulting engineering firm.” Recorded in the RevenueBase company graph · Sep 16, 2026 · View company records in RevenueBase
12	KCI	Exact match	Sparks, NC, United StatesHQ recorded Sep 16, 2026	1,001-5,000	2,207 contacts →
	Exact match “KCI is a 100-percent employee-owned engineering, consulting and construction firm serving clients throughout the United States and beyond.” Recorded in the RevenueBase company graph · Sep 16, 2026 · View company records in RevenueBase
13	Langan Engineering & Environmental Services	Exact match	Parsippany, NJ, United StatesHQ recorded Sep 16, 2026	1,001-5,000	2,177 contacts →
	Exact match “Langan's client-focused, highly entrepreneurial culture cultivates an environment of opportunities in which career growth and teamwork flourish.” Recorded in the RevenueBase company graph · Sep 16, 2026 · View company records in RevenueBase
14	Civil & Environmental Consultants, INC	Exact match	Moon Township, PA, United StatesHQ recorded Sep 16, 2026	1,001-5,000	2,145 contacts →
	Exact match “Civil & Environmental Consultants, Inc.(CEC) provides comprehensive market-oriented consulting services that advance the strategic business objectives of its clients.” Recorded in the RevenueBase company graph · Sep 16, 2026 · View company records in RevenueBase
15	Olsson	Exact match	Lincoln, NE, United StatesHQ recorded Sep 16, 2026	1,001-5,000	2,108 contacts →
	Exact match “Olsson is an engineering firm made up of people who craft expert solutions and designs that improve communities.” Recorded in the RevenueBase company graph · Sep 16, 2026 · View company records in RevenueBase
16	Hazen And Sawyer	Exact match	New York, NY, United StatesHQ recorded Sep 16, 2026	1,001-5,000	2,100 contacts →
	Exact match “As Hazen marks 75 years, we celebrate a legacy of absolute commitment to our clients while delivering the best technical work available anywhere.” Recorded in the RevenueBase company graph · Sep 16, 2026 · View company records in RevenueBase
17	IMEG	Exact match	Rock Island, IL, United StatesHQ recorded Sep 16, 2026	1,001-5,000	1,985 contacts →
	Exact match “Leaders in Engineering and Innovation.” Recorded in the RevenueBase company graph · Sep 16, 2026 · View company records in RevenueBase
18	LJA	Exact match	Houston, TX, United StatesHQ recorded Sep 16, 2026	1,001-5,000	1,932 contacts →
	Exact match “Employee-Owned.” Recorded in the RevenueBase company graph · Sep 16, 2026 · View company records in RevenueBase
19	Carollo Engineers	Exact match	Walnut Creek, CA, United StatesHQ recorded Sep 16, 2026	1,001-5,000	1,718 contacts →
	Exact match “For more than 90 years, Carollo Engineers has been dedicated exclusively to water and wastewater solutions.” Recorded in the RevenueBase company graph · Sep 16, 2026 · View company records in RevenueBase
20	Bowman Consulting	Exact match	Reston, VA, United StatesHQ recorded Sep 16, 2026	1,001-5,000	1,666 contacts →
	Exact match “Headquartered in Reston, Virginia, Bowman is a national engineering services firm delivering infrastructure solutions to customers who own, develop and maintain the built…” Recorded in the RevenueBase company graph · Sep 16, 2026 · View company records in RevenueBase
21	Rk&k	Exact match	Baltimore, MD, United StatesHQ recorded Sep 16, 2026	1,001-5,000	1,641 contacts →
	Exact match “RK & K is a full-service planning, engineering, environmental, and construction management/inspection firm serving a wide range of clients throughout the United States.” Recorded in the RevenueBase company graph · Sep 16, 2026 · View company records in RevenueBase
22	CHA Consulting, INC	Exact match	Albany, NY, United StatesHQ recorded Sep 16, 2026	1,001-5,000	1,639 contacts →
	Exact match “CHA Consulting, Inc.(CHA) is an innovative, full-service engineering, design, consulting, and program/construction management firm providing a wide range of technology-enhanced…” Recorded in the RevenueBase company graph · Sep 16, 2026 · View company records in RevenueBase
23	Swca Environmental Consultants	Exact match	Phoenix, AZ, United StatesHQ recorded Sep 16, 2026	1,001-5,000	1,629 contacts →
	Exact match “Founded on a commitment to sound science and creative solutions, SWCA is a leader in environmental and management consulting services.” Recorded in the RevenueBase company graph · Sep 16, 2026 · View company records in RevenueBase
24	GEI Consultants, INC	Exact match	Woburn, MA, United StatesHQ recorded Sep 16, 2026	1,001-5,000	1,604 contacts →
	Exact match Recorded description not available. Recorded in the RevenueBase company graph · Sep 16, 2026 · View company records in RevenueBase
25	UES	Exact match	Orlando, FL, United StatesHQ recorded Sep 16, 2026	1,001-5,000	1,595 contacts →
	Exact match “UES provides professional engineering, environmental, testing and inspection services to clients across the United States.” Recorded in the RevenueBase company graph · Sep 16, 2026 · View company records in RevenueBase

RevenueBase SmartSearch

Describe a niche business in your own words. RevenueBase SmartSearch compares the meaning of your description with company business descriptions compiled in the RevenueBase company graph. Exact, Similar, Related and Broad control how closely companies must fit.

This list uses Exact for “environmental engineering firms”. Each Exact match badge shows membership in that saved search; it is not an individual similarity score or a service-quality rating. Recorded descriptions are shown where available.

Showing 25 of 6,932 environmental engineering firms based in the United States

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Environmental engineering firms based in the United States at a glance

As of Sep 16, 2026

48.2%Verified-email coverage

44.8Average contacts per company

11-50Median size (employees)

2.0%Largest-city concentration · Houston

Sep 16, 2026Page data refreshed

Companies by employee count

1-10

2,943

11-50

2,642

51-200

940

201-500

227

501-1,000

1,001-5,000

5,001-10,000

10001+

Email recency for this list is measured worldwide rather than for United States, so it is reported there. Company counts and contact totals on this page are exact for United States, over 6,932 companies.

How this list was built

The recorded descriptions help you assess these company matches. Check a company’s website for its current services and locations.

Source: The RevenueBase company graph: 60 million companies and 398.9 million professional contacts resolved from primary sources, queried with RevenueBase SmartSearch, the natural-language company search available to every RevenueBase user.
What qualifies: Company records associated with the United States whose business descriptions match “environmental engineering firms” by meaning at the Exact setting. Descriptions are compiled in the RevenueBase company graph from public websites, profiles and company information where available; they are not guaranteed quotations from the company's website.
RevenueBase SmartSearch: Describe a niche company in your own words to find businesses by meaning. Exact, Similar, Related and Broad control the breadth of RevenueBase SmartSearch. This saved list uses Exact. Each row's Exact match badge shows inclusion in that search, not an individual score or a service-quality judgment.
Public preview: The public preview omits records without a verified work email. Where headquarters information is recorded, preview rows are also filtered to this page’s location. Dataset totals and geographic summaries describe the full matched records before these preview filters.
Match quality: RevenueBase's August 25, 2026 study assessed 4,198 description/company pairs across matching settings. The publisher reports 86% good or better at Exact. This evaluates the method across queries; it does not audit this individual list. Recorded company descriptions, where available, help you judge each match yourself. Read the full methodology: how the lists are built and what the study measures.
Ranking: Team size, largest first: companies are ordered by the number of professionals RevenueBase tracks at each one. Employee ranges shown are reported bands, for context.
Verification: Every displayed company carries at least one verified work email. RevenueBase tracks 149,573 professional contacts with verified work emails across the full matched dataset. Contacts re-verify on a rolling cadence, and each contact's own verification date is shown inside RevenueBase.
Refresh: This page's figures were pulled from the company graph on September 16, 2026. Lists refresh periodically as the graph is re-checked.
Record context: Company records and descriptions can change. Check the company's website for its current services and locations.

Environmental engineering firms by metro

Frequently asked

What is RevenueBase SmartSearch?

RevenueBase SmartSearch finds niche companies by the meaning of their business descriptions in the RevenueBase company graph. Exact, Similar, Related and Broad control how closely companies must fit your description. This list uses Exact for “environmental engineering firms”; each Exact match badge shows search membership, not an individual similarity or quality score.

How many environmental engineering firms are there based in the United States?

RevenueBase identified 6,932 company matches for environmental engineering firms associated with the United States as of September 2026, using the meaning of business descriptions at Exact. This is the recorded matched set in the RevenueBase company graph.

What is the largest company on this list?

Tetra Tech tops the displayed preview by professional contacts tracked in RevenueBase. Recorded headquarters appear in the company rows.

Which city has the most environmental engineering firms?

Houston leads with 138 company records, followed by New York (103) and Austin (73).

How do I get contact information for these companies?

A free RevenueBase account lets you run this exact search and work limited free results with 500 credits to start. Upgrading provides access to the 149,573 professional contacts with verified work emails tracked across these 6,932 companies; direct dials are available where recorded.

How current is this list?

The list refreshes periodically as the company graph is re-checked. This page's figures were pulled on September 16, 2026.

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About this data

RevenueBase is a B2B data infrastructure company. Its company graph covers 60 million companies and 398.9 million professional contacts, with emails verified on a rolling cadence rather than scraped once and left to decay. These company lists are generated directly from that graph with RevenueBase SmartSearch, the same natural-language company search every RevenueBase user has: describe a market in plain words, get the companies that match, and add verified emails and direct dials for the people at them. It is the same data that powers RevenueBase's B2B data products, and a free account includes 500 credits to start. How these lists are built and judged.