Company lists · Data refreshed September 2026

Top 25 Environmental permitting consultants based in the United States

RevenueBase identified 1,218 environmental permitting consultants headquartered in the United States as of September 2026 and tracks 20,017 professional contacts across them, including 10,641 with verified work emails. Houston is the largest hub.

This list covers environmental permitting consultants headquartered in the United States, matched on what each company actually does as described in its own words. Ranked by team size, largest first. Every row shows the company's own description, its RevenueBase Smart Search rating, and when it was last checked. Data refreshed September 19, 2026.

Published by RevenueBase, a B2B data infrastructure company. This list was built with RevenueBase Smart Search, 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 HQ checked on every row RevenueBase Smart Search rating on every row Refreshed Sep 19, 2026 86% judged on-target in blind review
1,218Companies
20,017Contacts tracked
10,641Verified emails
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The 25 largest environmental permitting consultants based in the United States

Ranked by team size
Top 25 of 1,218 environmental permitting consultants based in the United States, ranked by team size, largest first. Data refreshed Sep 19, 2026. RevenueBase Smart Search rates how each company's information relates to environmental permitting consultants: strong evidence (its own description names it), partial (names part of it), indirect (matched on the rest of its profile rather than the description shown). Click a contact count to view that company's people.
#CompanyRevenueBase Smart SearchHeadquartersEmployeesContacts
1Partial evidencePhoenix, AZ, United StatesHQ checked Sep 19, 20261,001-5,0001,629 contacts →

Partial evidence

“Founded on a commitment to sound science and creative solutions, SWCA is a leader in environmental and management consulting services.”

Source: RevenueBase Database · checked Sep 19, 2026
2Partial evidenceMinneapolis, MN, United StatesHQ checked Sep 19, 20261,001-5,0001,088 contacts →

Partial evidence

“Barr provides engineering and environmental consulting services to clients across the Midwest, throughout the Americas, and around the world.”

Source: RevenueBase Database · checked Sep 19, 2026
3Strong evidenceDallas, TX, United StatesHQ checked Sep 19, 20261,001-5,000961 contacts →

Strong evidence

“Trinity Consultants is a global team of experts helping organizations solve complex challenges in environmental compliance, ecological protection, infrastructure performance, and…”

Source: RevenueBase Database · checked Sep 19, 2026
4Indirect evidenceLafayette, LA, United StatesHQ checked Sep 19, 20261,001-5,000865 contacts →

Indirect evidence

“ATC Group Services LLC is now Atlas.”

Source: RevenueBase Database · checked Sep 19, 2026
5Partial evidenceSan Francisco, CA, United StatesHQ checked Sep 19, 2026501-1,000732 contacts →

Partial evidence

“ESA is a 100% employee-owned environmental consulting firm.”

Source: RevenueBase Database · checked Sep 19, 2026
6Partial evidenceWall Township, NJ, United StatesHQ checked Sep 19, 2026201-500447 contacts →

Partial evidence

“We are Groundwater & Environmental Services, Inc, better known as GES.”

Source: RevenueBase Database · checked Sep 19, 2026
7Strong evidenceGainesville, FL, United StatesHQ checked Sep 19, 2026201-500305 contacts →

Strong evidence

Environmental Consulting & Technology, Inc.(ECT) is a multi-disciplinary environmental and sustainability consulting firm delivering strategy, permitting, design, and management…”

Source: RevenueBase Database · checked Sep 19, 2026
8Partial evidenceGainesville, VA, United StatesHQ checked Sep 19, 2026201-500268 contacts →

Partial evidence

“For more than 30 years, WSSI has been the trusted partner in environmental, regulatory, cultural resources, and water resources engineering consulting.”

Source: RevenueBase Database · checked Sep 19, 2026
9Indirect evidenceBedford, NH, United StatesHQ checked Sep 19, 2026201-500189 contacts →

Indirect evidence

Source: RevenueBase Database · checked Sep 19, 2026
10Strong evidenceSan Rafael, CA, United StatesHQ checked Sep 19, 202651-200183 contacts →

Strong evidence

“WRA is an environmental consultancy that’s making a net positive impact.”

Source: RevenueBase Database · checked Sep 19, 2026
11Partial evidenceOakland, CA, United StatesHQ checked Sep 19, 2026201-500166 contacts →

Partial evidence

“Terraphase offers cost-effective solutions to complex environmental and engineering challenges.”

Source: RevenueBase Database · checked Sep 19, 2026
12Indirect evidenceRocklin, CA, United StatesHQ checked Sep 19, 202651-200166 contacts →

Indirect evidence

Source: RevenueBase Database · checked Sep 19, 2026
13Indirect evidenceFarmington, CT, United StatesHQ checked Sep 19, 202651-200155 contacts →

Indirect evidence

“For 40 years, the consulting engineers at HRP have worked together with our clients to assure that they reach their intended business goals and achieve the right solutions to…”

Source: RevenueBase Database · checked Sep 19, 2026
14Partial evidenceElmhurst, IL, United StatesHQ checked Sep 19, 202651-200140 contacts →

Partial evidence

“Since the passage of original environmental legislation nearly four decades ago, both private and public industry have turned to Mostardi Platt for guidance in complying with air…”

Source: RevenueBase Database · checked Sep 19, 2026
15Partial evidenceDallas, TX, United StatesHQ checked Sep 19, 202651-200136 contacts →

Partial evidence

“OUR MISSION is to combine sustainable environmental solutions with forward-thinking, cost-effective, innovative, and value-added technologies that balance our clients’ economic…”

Source: RevenueBase Database · checked Sep 19, 2026
16Indirect evidenceYaphank, NY, United StatesHQ checked Sep 19, 202651-200135 contacts →

Indirect evidence

“EnviroTrac Ltd.”

Source: RevenueBase Database · checked Sep 19, 2026
17Strong evidenceFort Collins, CO, United StatesHQ checked Sep 19, 202651-200129 contacts →

Strong evidence

“Ensero Solutions is an environmental consulting and remediation business with specific expertise in environmental assessments and permitting solutions, mine water management…”

Source: RevenueBase Database · checked Sep 19, 2026
18Strong evidencePhoenix, FL, United StatesHQ checked Sep 19, 202651-200126 contacts →

Strong evidence

“America's #1 Stormwater Consultants Earthworks Environmental, LLC provides top of the line storm water pollution prevention (SWPP/NPDES), erosion control and dust control…”

Source: RevenueBase Database · checked Sep 19, 2026
19Strong evidenceGreenwood Village, CO, United StatesHQ checked Sep 19, 202651-200126 contacts →

Strong evidence

“CMS Environmental Solutions is a stormwater compliance consultant providing NOI permitting, development, dewatering planning, site inspections, and custom stormwater management…”

Source: RevenueBase Database · checked Sep 19, 2026
20Indirect evidenceHouston, TX, United StatesHQ checked Sep 19, 202651-200116 contacts →

Indirect evidence

“Edge Engineering & Science, LLC (EDGE) is a privately owned professional services firm headquartered in Houston, Texas.”

Source: RevenueBase Database · checked Sep 19, 2026
21Indirect evidenceHarrisburg, PA, United StatesHQ checked Sep 19, 202651-200108 contacts →

Indirect evidence

“Established in 1969, Skelly and Loy is a privately owned, mid-sized corporation with 6 Mid-Atlantic offices.”

Source: RevenueBase Database · checked Sep 19, 2026
22Partial evidenceChantilly, VA, United StatesHQ checked Sep 19, 2026201-500104 contacts →

Partial evidence

“Established in 1983, TechLaw provides environmental and management consulting services to the public sector nationwide.”

Source: RevenueBase Database · checked Sep 19, 2026
23Partial evidenceCharlotte, NC, United StatesHQ checked Sep 19, 202651-200103 contacts →

Partial evidence

“Hart & Hickman PC provides environmental consulting services to commercial, industrial, and governmental clients throughout the Southeast US.”

Source: RevenueBase Database · checked Sep 19, 2026
24Partial evidenceBaton Rouge, LA, United StatesHQ checked Sep 19, 202651-200101 contacts →

Partial evidence

“CK Associates is an environmental consulting firm that is fully owned by its employees.”

Source: RevenueBase Database · checked Sep 19, 2026
25Partial evidenceMechanicsville, VA, United StatesHQ checked Sep 19, 202611-50101 contacts →

Partial evidence

“Consulting, Inc.(3e) is a dynamic and progressive certified small business that specializes in environmental studies, environmental engineering, environmental education, and…”

Source: RevenueBase Database · checked Sep 19, 2026

Showing 25 of 1,218 environmental permitting consultants based in the United States

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Environmental permitting consultants based in the United States at a glance

As of Sep 19, 2026
53.2%Verified-email coverage
16.4Average contacts per company
1-10Median size (employees)
2.7%Largest-city concentration · Houston
Sep 19, 2026Page data refreshed

Companies by employee count

1-10
714
11-50
403
51-200
77
201-500
14
501-1,000
2
1,001-5,000
5
10001+
1

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 1,218 companies.

How this list was built

Company categories are rarely black and white. RevenueBase reads each company's own description of its business to decide whether it belongs among environmental permitting consultants, so some rows will be adjacent to the category rather than pure plays. The description and RevenueBase Smart Search rating on every row are there so you can check each match yourself.

Source
The RevenueBase company graph: 60 million companies and 398.9 million professional contacts resolved from primary sources, queried with RevenueBase Smart Search, the natural-language company search available to every RevenueBase user.
What qualifies
Companies headquartered in the United States whose own description of what they do matches “environmental permitting consultants”. Matching reads each company's description, not its industry code or its name.
RevenueBase Smart Search
RevenueBase Smart Search is how this list is assembled and how each row is rated. RevenueBase's data engine and AI assess a company's LinkedIn profile, information supplied directly by the company, its website and other publicly available information, then relate it to a category defined in a user's own words. Each row is rated strong evidence (its own description names environmental permitting consultants), partial evidence (it names part of the category) or indirect evidence (the description shown names none of it and the match rests on the rest of the company's profile). The description supporting each rating is quoted on the row.
What we exclude
Companies whose own description does not clearly place them among environmental permitting consultants, and records with no verified work email. Companies headquartered outside United States are excluded even when they keep an office there.
Match quality
In blind human judging of this matching method, 86% of matched companies were on target. Expect roughly 1 in 7 rows to be adjacent to the category rather than a pure play. Every row shows the company's own description and its RevenueBase Smart Search rating so you can judge each match yourself. Read the full methodology: how the lists are built, how the judging worked, and what the figure means.
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 listed company carries at least one verified work email, 10,641 across the full list. 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 19, 2026. Lists refresh periodically as the graph is re-checked.
Corrections
Wrong category, wrong headquarters, or a company that has closed? Use “Report an issue” on any row. Reports go to the RevenueBase Data Team and feed back into the company graph.

Environmental permitting consultants by metro

  • Environmental permitting consultants in Houston33

Frequently asked

What is RevenueBase Smart Search?

RevenueBase Smart Search is how RevenueBase decides which companies belong on this list and how strongly each one fits. Its data engine and AI assess a company's LinkedIn profile, information supplied directly by the company, its website and other publicly available information, then relate it to the category the list is about. Each row is rated strong evidence when the company's own description names environmental permitting consultants, partial evidence when it names part of the category, and indirect evidence when the description shown names none of it and the match rests on the rest of the company's profile.

How many environmental permitting consultants are there based in the United States?

RevenueBase identified 1,218 environmental permitting consultants headquartered in the United States as of September 2026, matched on each company's own description of what it does rather than its industry code.

What is the largest company on this list?

Swca Environmental Consultants, headquartered in Phoenix, tops this list with the largest team on record.

Which city has the most environmental permitting consultants?

Houston leads with 33 headquartered companies, followed by Tampa (19) and Austin (16).

How do I get contact information for these companies?

A free RevenueBase account lets you run this exact search and work the top results, verified emails and direct dials included. Upgrading unlocks all 10,641 verified decision-maker contacts tracked across these 1,218 companies.

How current is this list?

The list refreshes periodically as the company graph is re-checked. This page's figures were pulled on September 19, 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 Smart Search, 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.