Company lists · Data refreshed September 2026

Top 25 Water resources management companies based in the United States

Name: Water resources management companies based in the United States
Creator: RevenueBase
License: https://creativecommons.org/licenses/by/4.0/

Compiled by the RevenueBase Data Team Data refreshed Sep 22, 2026 820 companies tracked

RevenueBase identified 820 water resources management companies headquartered in the United States as of September 2026 and tracks 59,270 professional contacts across them, including 27,928 with verified work emails. Houston is the largest hub.

This list covers water resources management companies 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 22, 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 22, 2026 86% judged on-target in blind review

820Companies

59,270Contacts tracked

27,928Verified emails

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The 25 largest water resources management companies based in the United States

Ranked by team size

Top 25 of 820 water resources management companies based in the United States, ranked by team size, largest first. Data refreshed Sep 22, 2026. RevenueBase Smart Search rates how each company's information relates to water resources management companies: 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.
#	Company	RevenueBase Smart Search	Headquarters	Employees	Contacts
1	Tetra Tech	Partial evidence	Pasadena, CA, United StatesHQ checked Sep 22, 2026	10001+	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 22, 2026
2	WSP In The U.S	Indirect evidence	New York, NY, United StatesHQ checked Sep 22, 2026	10001+	9,318 contacts →
	Indirect evidence “What if you could shape built and natural environments – and the future of those that use them?” Source: RevenueBase Database · checked Sep 22, 2026
3	Evoqua Water Technologies	Indirect evidence	Washington, DC, United StatesHQ checked Sep 22, 2026	10001+	2,639 contacts →
	Indirect evidence “Evoqua has now joined Xylem.” Source: RevenueBase Database · checked Sep 22, 2026
4	Brown And Caldwell	Indirect evidence	Walnut Creek, CA, United StatesHQ checked Sep 22, 2026	1,001-5,000	2,473 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 22, 2026
5	Hazen And Sawyer	Indirect evidence	New York, NY, United StatesHQ checked Sep 22, 2026	1,001-5,000	2,100 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 22, 2026
6	Carollo Engineers	Partial evidence	Walnut Creek, CA, United StatesHQ checked Sep 22, 2026	1,001-5,000	1,718 contacts →
	Partial evidence “For more than 90 years, Carollo Engineers has been dedicated exclusively to water and wastewater solutions.” Source: RevenueBase Database · checked Sep 22, 2026
7	Freese And Nichols	Indirect evidence	Fort Worth, TX, United StatesHQ checked Sep 22, 2026	1,001-5,000	1,496 contacts →
	Indirect evidence “Freese and Nichols is a professional planning, consulting and engineering firm serving clients across the United States.” Source: RevenueBase Database · checked Sep 22, 2026
8	AQUA	Partial evidence	Bryn Mawr, PA, United StatesHQ checked Sep 22, 2026	1,001-5,000	1,478 contacts →
	Partial evidence “Aqua is one of the largest U.S-based, publicly traded water and wastewater utilities, serving more than 3 million people in Illinois, Indiana, New Jersey, North Carolina…” Source: RevenueBase Database · checked Sep 22, 2026
9	Verdantas	Indirect evidence	Tampa, FL, United StatesHQ checked Sep 22, 2026	1,001-5,000	1,139 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 22, 2026
10	Inframark	Strong evidence	Horsham, PA, United StatesHQ checked Sep 22, 2026	1,001-5,000	973 contacts →
	Strong evidence “As an Azuria owned company, Inframark is a widely recognized leader in Water Infrastructure Operations and Infrastructure Management Services.” Source: RevenueBase Database · checked Sep 22, 2026
11	Valley Water	Strong evidence	San Jose, CA, United StatesHQ checked Sep 22, 2026	501-1,000	949 contacts →
	Strong evidence “Valley Water manages an integrated water resources system that includes the supply of clean, safe water, flood protection and stewardship of streams on behalf of Santa Clara…” Source: RevenueBase Database · checked Sep 22, 2026
12	Parametrix	Indirect evidence	Seattle, WA, United StatesHQ checked Sep 22, 2026	501-1,000	880 contacts →
	Indirect evidence “At Parametrix, we help our clients imagine what's possible.” Source: RevenueBase Database · checked Sep 22, 2026
13	ATC Group Services LLC	Indirect evidence	Lafayette, LA, United StatesHQ checked Sep 22, 2026	1,001-5,000	865 contacts →
	Indirect evidence “ATC Group Services LLC is now Atlas.” Source: RevenueBase Database · checked Sep 22, 2026
14	DUDEK	Indirect evidence	Encinitas, CA, United StatesHQ checked Sep 22, 2026	501-1,000	795 contacts →
	Indirect evidence “Dudek is an environmental, planning, and engineering consulting firm.” Source: RevenueBase Database · checked Sep 22, 2026
15	Psomas	Indirect evidence	Los Angeles, CA, United StatesHQ checked Sep 22, 2026	501-1,000	748 contacts →
	Indirect evidence “Our award-winning projects are produced through innovation, creativity, and technical expertise.” Source: RevenueBase Database · checked Sep 22, 2026
16	Tighe & Bond	Indirect evidence	Westfield, MA, United StatesHQ checked Sep 22, 2026	501-1,000	646 contacts →
	Indirect evidence “Tighe & Bond is the Northeast’s leading engineering, environmental, planning, and design consulting firm.” Source: RevenueBase Database · checked Sep 22, 2026
17	Kennedy Jenks	Partial evidence	San Francisco, CA, United StatesHQ checked Sep 22, 2026	201-500	578 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 22, 2026
18	Dupont Water Solutions	Indirect evidence	Wilmington, DE, United StatesHQ checked Sep 22, 2026	10001+	470 contacts →
	Indirect evidence “We’re helping companies in every industry, in every corner of the globe make real progress.” Source: RevenueBase Database · checked Sep 22, 2026
19	Baxter & Woodman	Indirect evidence	Crystal Lake, IL, United StatesHQ checked Sep 22, 2026	201-500	385 contacts →
	Indirect evidence “Founded in 1946, Baxter & Woodman, Inc.” Source: RevenueBase Database · checked Sep 22, 2026
20	Ae2s Advanced Engineering And Environmental Services, LLC	Indirect evidence	Grand Forks, ND, United StatesHQ checked Sep 22, 2026	201-500	339 contacts →
	Indirect evidence “AE2S is a specialized civil/environmental consulting engineering firm that provides professional services and our unique brand of extreme client service to clients in the upper…” Source: RevenueBase Database · checked Sep 22, 2026
21	Tata & Howard, INC	Indirect evidence	Marlborough, MA, United StatesHQ checked Sep 22, 2026	51-200	315 contacts →
	Indirect evidence “Tata & Howard is a 100% employee owned, award-winning, specialized consulting engineering firm dedicated to providing superior client service coupled with delivering…” Source: RevenueBase Database · checked Sep 22, 2026
22	Aquarion Water Company	Partial evidence	Bridgeport, CT, United StatesHQ checked Sep 22, 2026	201-500	308 contacts →
	Partial evidence “Aquarion Water Company is the public water supply and wastewater treatment company for more than people in 73 cities and towns in Connecticut, Massachusetts and New Hampshire.” Source: RevenueBase Database · checked Sep 22, 2026
23	Environmental Consulting & Technology, Inc. ECT	Partial evidence	Gainesville, FL, United StatesHQ checked Sep 22, 2026	201-500	305 contacts →
	Partial 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 22, 2026
24	Csrs, A Westwood Company	Indirect evidence	Baton Rouge, LA, United StatesHQ checked Sep 22, 2026	51-200	305 contacts →
	Indirect evidence “CSRS was acquired by Westwood Professional Services on June 30, 2025.” Source: RevenueBase Database · checked Sep 22, 2026
25	West Yost	Partial evidence	Davis, CA, United StatesHQ checked Sep 22, 2026	201-500	279 contacts →
	Partial evidence “West Yost is a water-focused consulting engineering firm ranked by Fortune Magazine as one of the “Best Small and Medium Workplaces in Consulting and Professional Services” 2023 -…” Source: RevenueBase Database · checked Sep 22, 2026

RevenueBase Smart Search

RevenueBase Smart Search assesses information from a company’s LinkedIn profile, information supplied directly by the company, its website, and other publicly available sources. It uses that information to rate how closely the company relates to this list’s category: water resources management companies. Every row carries its rating and the description the rating was read from, so each one can be checked rather than taken on trust.

Strong evidence: The company's own public description of its business names water resources management companies.
Partial evidence: Its own public description names part of water resources management companies, so it works in or next to the category without describing itself that way.
Indirect evidence: The description shown does not name water resources management companies. The match rests on the rest of the company's public profile rather than the one sentence quoted here, so this is the rating to check first.

RevenueBase Smart Search is how these lists are built: RevenueBase's data engine and AI assemble the companies that match a category defined in a user's own words, so a list can be about what companies actually do rather than about whichever industry code they were filed under.

Showing 25 of 820 water resources management companies based in the United States

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Water resources management companies based in the United States at a glance

As of Sep 22, 2026

47.1%Verified-email coverage

72.3Average contacts per company

1-10Median size (employees)

2.3%Largest-city concentration · Houston

Sep 22, 2026Page data refreshed

Companies by employee count

1-10

414

11-50

234

51-200

109

201-500

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 820 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 management companies, 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 management companies”. 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 management companies), 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 management companies, 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, 27,928 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 22, 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.

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 management companies, 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 management companies are there based in the United States?

RevenueBase identified 820 water resources management companies 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?

Tetra Tech, headquartered in Pasadena, tops this list with the largest team on record.

Which city has the most water resources management companies?

Houston leads with 19 headquartered companies, followed by Denver (14) and Portland (13).

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 27,928 verified decision-maker contacts tracked across these 820 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 22, 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.