Company lists · Data refreshed September 2026

Top 25 Hydrogeology companies worldwide

Name: Hydrogeology companies worldwide
Creator: RevenueBase
License: https://creativecommons.org/licenses/by/4.0/

Compiled by the RevenueBase Data Team Data refreshed Sep 21, 2026 15,490 companies tracked

RevenueBase identified 15,490 hydrogeology companies worldwide as of September 2026 and tracks 297,864 professional contacts across them, including 89,698 with verified work emails. The United States is the largest market and Houston the largest hub.

This list covers hydrogeology companies worldwide, 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. Country and city lists for hydrogeology companies follow the table.

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

15,490Companies

297,864Contacts tracked

89,698Verified emails

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The 25 largest hydrogeology companies worldwide

Ranked by team size

Top 25 of 15,490 hydrogeology companies worldwide, 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	Golder	Indirect evidence	Vancouver, BC, CanadaHQ checked Sep 21, 2026	5,001-10,000	3,167 contacts →
	Indirect evidence “Golder was acquired by WSP.” Source: RevenueBase Database · checked Sep 21, 2026
5	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
6	SRK Consulting	Indirect evidence	Vancouver, CanadaHQ checked Sep 21, 2026	1,001-5,000	2,259 contacts →
	Indirect evidence “SRK Consulting is an independent, international group providing specialised consultancy services.” Source: RevenueBase Database · checked Sep 21, 2026
7	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
8	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
9	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
10	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
11	Major Drilling	Indirect evidence	Moncton, NB, CanadaHQ checked Sep 21, 2026	1,001-5,000	1,447 contacts →
	Indirect evidence “Major Drilling Group International Inc.” Source: RevenueBase Database · checked Sep 21, 2026
12	DHI	Indirect evidence	Hørsholm, DenmarkHQ checked Sep 21, 2026	1,001-5,000	1,427 contacts →
	Indirect evidence “There is no substitute for water.” Source: RevenueBase Database · checked Sep 21, 2026
13	Geosol Geologia E Sondagens S.A	Indirect evidence	Belo Horizonte, BrazilHQ checked Sep 21, 2026	1,001-5,000	1,317 contacts →
	Indirect evidence “One of the leading geology companies in the world, GEOSOL excels in the undertaking of geological drilling and mineral engineering programs.” Source: RevenueBase Database · checked Sep 21, 2026
14	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
15	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
16	BGP International	Indirect evidence	涿州, ChinaHQ checked Sep 21, 2026	5,001-10,000	1,097 contacts →
	Indirect evidence “BGP is one of the world's competitive geophysical companies, delivering a wide range of geophysical products and services.” Source: RevenueBase Database · checked Sep 21, 2026
17	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
18	Deltares	Indirect evidence	Delft, NetherlandsHQ checked Sep 21, 2026	501-1,000	1,021 contacts →
	Indirect evidence “Deltares is an independent knowledge institute for applied research in the field of water and subsurface.” Source: RevenueBase Database · checked Sep 21, 2026
19	Carso Perforación	Indirect evidence	United StatesHQ checked Sep 21, 2026	1,001-5,000	994 contacts →
	Indirect evidence “Empresa líder en el Sector Petrolero, con presencia a Nivel Nacional, principales clientes PEMEX Y CFE, con servicios como perforación de pozos terrestres, Marinos, Geotérmicos…” Source: RevenueBase Database · checked Sep 21, 2026
20	WSP EN Chile	Indirect evidence	Vitacura, ChileHQ checked Sep 21, 2026	10001+	988 contacts →
	Indirect evidence “WSP en una empresa líder en servicios profesionales de consultoría en recursos hídricos, ingeniería, medio ambiente y sustentabilidad.” Source: RevenueBase Database · checked Sep 21, 2026
21	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
22	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
23	Klohn Crippen Berger	Indirect evidence	Vancouver, BC, CanadaHQ checked Sep 21, 2026	501-1,000	871 contacts →
	Indirect evidence “KCB is a global engineering, geosciences, and environmental consulting firm driven by Passion, Integrity and a commitment to Excellence.” Source: RevenueBase Database · checked Sep 21, 2026
24	BGC Engineering INC	Indirect evidence	Vancouver, BC, CanadaHQ checked Sep 21, 2026	501-1,000	798 contacts →
	Indirect evidence “BGC Engineering is an international consulting firm that provides professional services in applied earth sciences.” Source: RevenueBase Database · checked Sep 21, 2026
25	AGR	Indirect evidence	Oslo, NorwayHQ checked Sep 21, 2026	501-1,000	768 contacts →
	Indirect evidence “AGR – an Aqualis company – is a multidisciplinary consultancy, specialising in drilling & wells, subsurface, marine and subsea solutions, resourcing, technical safety and software…” 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 15,490 hydrogeology companies worldwide

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Hydrogeology companies worldwide at a glance

As of Sep 21, 2026

30.1%Verified-email coverage

19.2Average contacts per company

1-10Median size (employees)

1.2%Largest-city concentration · Houston

Sep 21, 2026Page data refreshed

Companies by employee count

1-10

7,987

11-50

5,067

51-200

1,686

201-500

429

501-1,000

113

1,001-5,000

5,001-10,000

10001+

Email recency is reported on each country list linked below.

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.
Coverage: Every country. Country and city lists for hydrogeology companies are linked below.
What qualifies: Companies worldwide 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.
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, 89,698 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 location

56 lists · largest first

Every Hydrogeology companies list RevenueBase publishes, by country and city. Counts are matching companies in each list as of its own refresh date.

Countries

Cities

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 worldwide?

RevenueBase identified 15,490 hydrogeology companies worldwide 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 country has the most hydrogeology companies?

The United States leads with 3,115 companies, followed by Brazil (1,072) and Canada (803). Every hydrogeology companies list by country and city is linked on this page.

Which city has the most hydrogeology companies?

Houston leads with 192 headquartered companies, followed by Calgary (162) and Belo Horizonte (139).

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 89,698 verified decision-maker contacts tracked across these 15,490 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.