Company lists · Data refreshed September 2026

Top 25 Hydrogeology companies based in the United States

Name: Hydrogeology 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 21, 2026 3,115 companies tracked

RevenueBase identified 3,115 hydrogeology companies headquartered in the United States as of September 2026 and tracks 141,143 professional contacts across them, including 53,180 with verified work emails. Houston is the largest hub.

This list covers hydrogeology 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 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

3,115Companies

141,143Contacts tracked

53,180Verified emails

Explore this list → Free signup · no credit card · 500 free credits

The 25 largest hydrogeology companies based in the United States

Ranked by team size

Top 25 of 3,115 hydrogeology companies 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 hydrogeology 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	Halliburton	Indirect evidence	Houston, TX, United StatesHQ checked Sep 21, 2026	10001+	53,380 contacts →
	Indirect evidence “We collaborate and engineer solutions to maximize asset value for our customers.” Source: RevenueBase Database · checked Sep 21, 2026
2	Tetra Tech	Indirect evidence	Pasadena, CA, United StatesHQ checked Sep 21, 2026	10001+	12,999 contacts →
	Indirect 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
3	Terracon	Indirect evidence	Olathe, KS, United StatesHQ checked Sep 21, 2026	5,001-10,000	6,113 contacts →
	Indirect evidence “Terracon is a 100 percent employee-owned consulting engineering firm providing quality services to clients.” Source: RevenueBase Database · checked Sep 21, 2026
4	Brown And Caldwell	Indirect evidence	Walnut Creek, CA, United StatesHQ checked Sep 21, 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 21, 2026
5	ECS Group Of Companies	Indirect evidence	Chantilly, VA, United StatesHQ checked Sep 21, 2026	1,001-5,000	2,210 contacts →
	Indirect evidence “ECS Group of Companies is a Chantilly, VA-based consulting engineering firm.” Source: RevenueBase Database · checked Sep 21, 2026
6	Langan Engineering & Environmental Services	Indirect evidence	Parsippany, NJ, United StatesHQ checked Sep 21, 2026	1,001-5,000	2,177 contacts →
	Indirect evidence “Langan's client-focused, highly entrepreneurial culture cultivates an environment of opportunities in which career growth and teamwork flourish.” Source: RevenueBase Database · checked Sep 21, 2026
7	Hazen And Sawyer	Indirect evidence	New York, NY, United StatesHQ checked Sep 21, 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 21, 2026
8	Select Water Solutions	Indirect evidence	Gainesville, TX, United StatesHQ checked Sep 21, 2026	1,001-5,000	1,605 contacts →
	Indirect evidence “Select is a leader in water management and chemical technology to our customers in the oil and gas industry, as well as in other industrial applications.” Source: RevenueBase Database · checked Sep 21, 2026
9	Newpark	Indirect evidence	Katy, TX, United StatesHQ checked Sep 21, 2026	1,001-5,000	1,244 contacts →
	Indirect evidence “Newpark Fluids Systems is the world’s leading pure-play oil & gas and geothermal fluid solutions provider.” Source: RevenueBase Database · checked Sep 21, 2026
10	Knight Piesold	Indirect evidence	Denver, CO, United StatesHQ checked Sep 21, 2026	1,001-5,000	1,231 contacts →
	Indirect 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
11	Woodard & Curran	Indirect evidence	Portland, ME, United StatesHQ checked Sep 21, 2026	1,001-5,000	1,060 contacts →
	Indirect 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
12	Aquatech	Indirect evidence	Canonsburg, PA, United StatesHQ checked Sep 21, 2026	501-1,000	903 contacts →
	Indirect evidence “Aquatech enables the world's most recognized companies to solve complex challenges in water reuse, desalination, minimal and zero liquid discharge, and critical minerals…” Source: RevenueBase Database · checked Sep 21, 2026
13	GZA Geoenvironmental, INC	Indirect evidence	Norwood, MA, United StatesHQ checked Sep 21, 2026	501-1,000	880 contacts →
	Indirect evidence “Founded in 1964 as a soils and foundations specialty consultant, GZA GeoEnvironmental, Inc.(GZA) has grown into a full-service company providing its clients with highly…” Source: RevenueBase Database · checked Sep 21, 2026
14	Shimmick Corporation	Indirect evidence	Irvine, CA, United StatesHQ checked Sep 21, 2026	1,001-5,000	760 contacts →
	Indirect evidence “At Shimmick (NASDAQ: SHIM), we’re shaping the future of sustainable infrastructure through innovative solutions that advance communities and protect our environment.” Source: RevenueBase Database · checked Sep 21, 2026
15	Schnabel Engineering	Indirect evidence	Glen Allen, VA, United StatesHQ checked Sep 21, 2026	501-1,000	707 contacts →
	Indirect evidence “Schnabel is a trusted partner in building the foundation for project success.” Source: RevenueBase Database · checked Sep 21, 2026
16	Raba Kistner, INC	Indirect evidence	San Antonio, TX, United StatesHQ checked Sep 21, 2026	501-1,000	582 contacts →
	Indirect evidence “Founded in 1968, Raba Kistner Inc.” Source: RevenueBase Database · checked Sep 21, 2026
17	Kennedy Jenks	Indirect evidence	San Francisco, CA, United StatesHQ checked Sep 21, 2026	201-500	578 contacts →
	Indirect 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
18	Trihydro Corporation	Indirect evidence	Laramie, WY, United StatesHQ checked Sep 21, 2026	501-1,000	577 contacts →
	Indirect 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
19	Nova Engineering And Environmental, LLC	Indirect evidence	Kennesaw, GA, United StatesHQ checked Sep 21, 2026	501-1,000	518 contacts →
	Indirect evidence “Established in 1996, NOVA was originally founded to provide Environmental Consulting, Geotechnical Engineering, and Construction Materials Testing and Inspection services to the…” Source: RevenueBase Database · checked Sep 21, 2026
20	Anchor QEA	Indirect evidence	Seattle, WA, United StatesHQ checked Sep 21, 2026	501-1,000	479 contacts →
	Indirect evidence “Headquartered in Seattle, Washington, Anchor QEA is a nationally recognized environmental science and engineering consulting firm specializing in aquatic, shoreline, and water…” Source: RevenueBase Database · checked Sep 21, 2026
21	Geoengineers INC	Indirect evidence	Redmond, WA, United StatesHQ checked Sep 21, 2026	201-500	479 contacts →
	Indirect evidence Source: RevenueBase Database · checked Sep 21, 2026
22	Ninyo & Moore, A Socotec Company	Indirect evidence	San Diego, CA, United StatesHQ checked Sep 21, 2026	501-1,000	449 contacts →
	Indirect evidence “Ninyo & Moore was acquired by SOCOTEC US.” Source: RevenueBase Database · checked Sep 21, 2026
23	MWH	Indirect evidence	Broomfield, CO, United StatesHQ checked Sep 21, 2026	501-1,000	428 contacts →
	Indirect evidence “As a leading U.S.” Source: RevenueBase Database · checked Sep 21, 2026
24	Express Energy Services	Indirect evidence	Houston, TX, United StatesHQ checked Sep 21, 2026	501-1,000	379 contacts →
	Indirect evidence “Express Energy Services, a leading oilfield services company, is active in every major hydrocarbon basin in the United States and is a premier provider of products and services…” Source: RevenueBase Database · checked Sep 21, 2026
25	CME Associates	Indirect evidence	Parlin, NJ, United StatesHQ checked Sep 21, 2026	201-500	336 contacts →
	Indirect evidence “CME Associates, with eight (8) office locations throughout New Jersey, provides a complete range of Environmental, Geotechnical, Engineering, Surveying and Planning services.” Source: RevenueBase Database · checked Sep 21, 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: hydrogeology 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 hydrogeology companies.
Partial evidence: Its own public description names part of hydrogeology companies, so it works in or next to the category without describing itself that way.
Indirect evidence: The description shown does not name hydrogeology 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 3,115 hydrogeology companies based in the United States

See the full list, filter by size, metro and specialty, and get verified emails and direct dials for all 53,180 reachable decision-makers.

Free signup · no credit card

View the full list →

Hydrogeology companies based in the United States at a glance

As of Sep 21, 2026

37.7%Verified-email coverage

45.3Average contacts per company

11-50Median size (employees)

6.2%Largest-city concentration · Houston

Sep 21, 2026Page data refreshed

Companies by employee count

1-10

1,492

11-50

1,121

51-200

373

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 3,115 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 hydrogeology 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 “hydrogeology 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 hydrogeology 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 hydrogeology 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, 53,180 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.

Hydrogeology companies by metro

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 hydrogeology 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 hydrogeology companies are there based in the United States?

RevenueBase identified 3,115 hydrogeology 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?

Halliburton, headquartered in Houston, tops this list with the largest team on record.

Which city has the most hydrogeology companies?

Houston leads with 192 headquartered companies, followed by Denver (55) and Austin (35).

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 53,180 verified decision-maker contacts tracked across these 3,115 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.

Ready to reach these companies? Verified emails and direct dials for all 3,115 hydrogeology companies based in the United States. Start with a free account, no credit card.

Download this list →

Related lists

Hydrogeology companies by geography

Browse the directory

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.