Company lists · Data refreshed September 2026

Top 25 Water resources consulting firms based in the United States

RevenueBase identified 1,465 water resources consulting firms headquartered in the United States as of September 2026 and tracks 141,881 professional contacts across them, including 62,004 with verified work emails. Houston is the largest hub.

This list covers water resources consulting firms 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 21, 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 21, 2026 86% judged on-target in blind review
1,465Companies
141,881Contacts tracked
62,004Verified emails
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The 25 largest water resources consulting firms based in the United States

Ranked by team size
Top 25 of 1,465 water resources consulting firms based in the United States, ranked by team size, largest first. Data refreshed Sep 21, 2026. RevenueBase Smart Search rates how each company's information relates to water resources consulting firms: 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
1Indirect evidenceDallas, TX, United StatesHQ checked Sep 21, 202610001+63,914 contacts →

Indirect evidence

“AECOM is the global infrastructure leader, committed to delivering a better world.”

Source: RevenueBase Database · checked Sep 21, 2026
2Partial evidencePasadena, CA, United StatesHQ checked Sep 21, 202610001+12,999 contacts →

Partial evidence

“Tetra Tech is the leader in water, environment and sustainable infrastructure, providing high-end technical and engineering services for projects worldwide.”

Source: RevenueBase Database · checked Sep 21, 2026
3Partial evidenceOlathe, KS, United StatesHQ checked Sep 21, 20265,001-10,0006,113 contacts →

Partial evidence

“Terracon is a 100 percent employee-owned consulting engineering firm providing quality services to clients.”

Source: RevenueBase Database · checked Sep 21, 2026
4Indirect evidenceWalnut Creek, CA, United StatesHQ checked Sep 21, 20261,001-5,0002,473 contacts →

Indirect evidence

“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.”

Source: RevenueBase Database · checked Sep 21, 2026
5Partial evidenceBoca Raton, FL, United StatesHQ checked Sep 21, 20261,001-5,0002,393 contacts →

Partial evidence

“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…”

Source: RevenueBase Database · checked Sep 21, 2026
6Partial evidenceMoon Township, PA, United StatesHQ checked Sep 21, 20261,001-5,0002,145 contacts →

Partial evidence

“Civil & Environmental Consultants, Inc.(CEC) provides comprehensive market-oriented consulting services that advance the strategic business objectives of its clients.”

Source: RevenueBase Database · checked Sep 21, 2026
7Indirect evidenceNew York, NY, United StatesHQ checked Sep 21, 20261,001-5,0002,100 contacts →

Indirect evidence

“As Hazen marks 75 years, we celebrate a legacy of absolute commitment to our clients while delivering the best technical work available anywhere.”

Source: RevenueBase Database · checked Sep 21, 2026
8Partial evidenceWalnut Creek, CA, United StatesHQ checked Sep 21, 20261,001-5,0001,718 contacts →

Partial evidence

“For more than 90 years, Carollo Engineers has been dedicated exclusively to water and wastewater solutions.”

Source: RevenueBase Database · checked Sep 21, 2026
9Partial evidencePhoenix, AZ, United StatesHQ checked Sep 21, 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 21, 2026
10Indirect evidenceWoburn, MA, United StatesHQ checked Sep 21, 20261,001-5,0001,604 contacts →

Indirect evidence

Source: RevenueBase Database · checked Sep 21, 2026
11Partial evidenceFort Worth, TX, United StatesHQ checked Sep 21, 20261,001-5,0001,496 contacts →

Partial evidence

“Freese and Nichols is a professional planning, consulting and engineering firm serving clients across the United States.”

Source: RevenueBase Database · checked Sep 21, 2026
12Strong evidenceDenver, CO, United StatesHQ checked Sep 21, 20261,001-5,0001,231 contacts →

Strong evidence

“Knight Piésold is an employee-owned, global consulting firm providing specialist services to the mining, power, water resources, and infrastructure industries.”

Source: RevenueBase Database · checked Sep 21, 2026
13Indirect evidenceTampa, FL, United StatesHQ checked Sep 21, 20261,001-5,0001,139 contacts →

Indirect evidence

“At Verdantas, we blend engineering and environmental science together with advanced technology and world-renowned labs to create solutions with the big picture in mind.”

Source: RevenueBase Database · checked Sep 21, 2026
14Indirect evidenceRockville, MD, United StatesHQ checked Sep 21, 20261,001-5,0001,137 contacts →

Indirect evidence

“Who is Apex?”

Source: RevenueBase Database · checked Sep 21, 2026
15Partial evidenceMinneapolis, MN, United StatesHQ checked Sep 21, 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 21, 2026
16Strong evidencePortland, ME, United StatesHQ checked Sep 21, 20261,001-5,0001,060 contacts →

Strong evidence

“Woodard & Curran is more than just a consulting firm – we are an employee-owned integrated science, engineering, design-build, and operations company specializing in water and…”

Source: RevenueBase Database · checked Sep 21, 2026
17Indirect evidenceSeattle, WA, United StatesHQ checked Sep 21, 2026501-1,000880 contacts →

Indirect evidence

“At Parametrix, we help our clients imagine what's possible.”

Source: RevenueBase Database · checked Sep 21, 2026
18Indirect evidenceLafayette, LA, United StatesHQ checked Sep 21, 20261,001-5,000865 contacts →

Indirect evidence

“ATC Group Services LLC is now Atlas.”

Source: RevenueBase Database · checked Sep 21, 2026
19Partial evidenceEncinitas, CA, United StatesHQ checked Sep 21, 2026501-1,000795 contacts →

Partial evidence

“Dudek is an environmental, planning, and engineering consulting firm.”

Source: RevenueBase Database · checked Sep 21, 2026
20Indirect evidenceDe Pere, WI, United StatesHQ checked Sep 21, 2026501-1,000781 contacts →

Indirect evidence

“By combining science, engineering, and technology with a true collaborative spirit, Foth has delivered innovative solutions to our clients since 1938.”

Source: RevenueBase Database · checked Sep 21, 2026
21Indirect evidenceLos Angeles, CA, United StatesHQ checked Sep 21, 2026501-1,000748 contacts →

Indirect evidence

“Our award-winning projects are produced through innovation, creativity, and technical expertise.”

Source: RevenueBase Database · checked Sep 21, 2026
22Partial evidenceSan Francisco, CA, United StatesHQ checked Sep 21, 2026501-1,000732 contacts →

Partial evidence

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

Source: RevenueBase Database · checked Sep 21, 2026
23Partial evidenceSan Francisco, CA, United StatesHQ checked Sep 21, 2026201-500578 contacts →

Partial evidence

“For over 100 years, Kennedy Jenks has provided engineering and scientific solutions for innovative water and environmental projects.”

Source: RevenueBase Database · checked Sep 21, 2026
24Strong evidenceLaramie, WY, United StatesHQ checked Sep 21, 2026501-1,000577 contacts →

Strong evidence

“Headquartered in Laramie, Wyoming, Trihydro provides environmental consulting, engineering and surveying, air quality and process management, information technology, and water and…”

Source: RevenueBase Database · checked Sep 21, 2026
25Partial evidenceBoston, MA, United StatesHQ checked Sep 21, 202651-200504 contacts →

Partial evidence

“BSC Group, Inc.(BSC) is a multidisciplinary consulting firm with a staff of more than 200 professionals and offices in Boston, Worcester, Andover, and West Yarmouth, MA, as well…”

Source: RevenueBase Database · checked Sep 21, 2026

Showing 25 of 1,465 water resources consulting firms based in the United States

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Water resources consulting firms based in the United States at a glance

As of Sep 21, 2026
43.7%Verified-email coverage
96.8Average contacts per company
1-10Median size (employees)
1.8%Largest-city concentration · Houston
Sep 21, 2026Page data refreshed

Companies by employee count

1-10
774
11-50
467
51-200
139
201-500
40
501-1,000
12
1,001-5,000
22
5,001-10,000
4
10001+
4

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 1,465 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 water resources consulting firms, 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 “water resources consulting firms”. 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 water resources consulting firms), 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 water resources consulting firms, 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, 62,004 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 21, 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.

Water resources consulting firms by metro

  • Water resources consulting firms in Houston27
  • Water resources consulting firms in Portland25

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 water resources consulting firms, 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 water resources consulting firms are there based in the United States?

RevenueBase identified 1,465 water resources consulting firms 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?

AECOM, headquartered in Dallas, tops this list with the largest team on record.

Which city has the most water resources consulting firms?

Houston leads with 27 headquartered companies, followed by Portland (25) and Seattle (21).

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 62,004 verified decision-maker contacts tracked across these 1,465 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 21, 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.