Company lists · Data refreshed September 2026
Top 25 Hydrological consulting firms worldwide
RevenueBase identified 7,057 hydrological consulting firms worldwide as of September 2026 and tracks 143,888 professional contacts across them, including 58,720 with verified work emails. The United States is the largest market and Belo Horizonte the largest hub.
This list covers hydrological consulting firms 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 28, 2026. Country and city lists for hydrological consulting firms 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.
The 25 largest hydrological consulting firms worldwide
Ranked by team size| # | Company | Contacts | |||
|---|---|---|---|---|---|
| 1 | 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 28, 2026Thanks. The Data Team will review it. | |||||
| 2 | 6,113 contacts → | ||||
Partial evidence “Terracon is a 100 percent employee-owned consulting engineering firm providing quality services to clients.” Source: RevenueBase Database · checked Sep 28, 2026Thanks. The Data Team will review it. | |||||
| 3 | 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 28, 2026Thanks. The Data Team will review it. | |||||
| 4 | 2,393 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 28, 2026Thanks. The Data Team will review it. | |||||
| 5 | 2,210 contacts → | ||||
Partial evidence “ECS Group of Companies is a Chantilly, VA-based consulting engineering firm.” Source: RevenueBase Database · checked Sep 28, 2026Thanks. The Data Team will review it. | |||||
| 6 | 2,145 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 28, 2026Thanks. The Data Team will review it. | |||||
| 7 | 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 28, 2026Thanks. The Data Team will review it. | |||||
| 8 | 1,718 contacts → | ||||
Indirect evidence “For more than 90 years, Carollo Engineers has been dedicated exclusively to water and wastewater solutions.” Source: RevenueBase Database · checked Sep 28, 2026Thanks. The Data Team will review it. | |||||
| 9 | 1,604 contacts → | ||||
Indirect evidence Source: RevenueBase Database · checked Sep 28, 2026Thanks. The Data Team will review it. | |||||
| 10 | 1,496 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 28, 2026Thanks. The Data Team will review it. | |||||
| 11 | 1,427 contacts → | ||||
Indirect evidence “There is no substitute for water.” Source: RevenueBase Database · checked Sep 28, 2026Thanks. The Data Team will review it. | |||||
| 12 | 1,231 contacts → | ||||
Partial 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 28, 2026Thanks. The Data Team will review it. | |||||
| 13 | 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 28, 2026Thanks. The Data Team will review it. | |||||
| 14 | 1,137 contacts → | ||||
Indirect evidence “Who is Apex?” Source: RevenueBase Database · checked Sep 28, 2026Thanks. The Data Team will review it. | |||||
| 15 | 1,088 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 28, 2026Thanks. The Data Team will review it. | |||||
| 16 | 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 28, 2026Thanks. The Data Team will review it. | |||||
| 17 | 880 contacts → | ||||
Indirect evidence “At Parametrix, we help our clients imagine what's possible.” Source: RevenueBase Database · checked Sep 28, 2026Thanks. The Data Team will review it. | |||||
| 18 | 871 contacts → | ||||
Partial 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 28, 2026Thanks. The Data Team will review it. | |||||
| 19 | 865 contacts → | ||||
Indirect evidence “ATC Group Services LLC is now Atlas.” Source: RevenueBase Database · checked Sep 28, 2026Thanks. The Data Team will review it. | |||||
| 20 | 842 contacts → | ||||
Indirect evidence “Together with our strategic partners, we can address everything from supporting vulnerable customers, water quality, asset performance and leak detection, to integrated planning…” Source: RevenueBase Database · checked Sep 28, 2026Thanks. The Data Team will review it. | |||||
| 21 | 798 contacts → | ||||
Partial evidence “BGC Engineering is an international consulting firm that provides professional services in applied earth sciences.” Source: RevenueBase Database · checked Sep 28, 2026Thanks. The Data Team will review it. | |||||
| 22 | 795 contacts → | ||||
Partial evidence “Dudek is an environmental, planning, and engineering consulting firm.” Source: RevenueBase Database · checked Sep 28, 2026Thanks. The Data Team will review it. | |||||
| 23 | 762 contacts → | ||||
Indirect evidence “This page is now closed.” Source: RevenueBase Database · checked Sep 28, 2026Thanks. The Data Team will review it. | |||||
| 24 | 737 contacts → | ||||
Indirect evidence “Antea Group est une société internationale d’ingénierie et de conseil en environnement.” Source: RevenueBase Database · checked Sep 28, 2026Thanks. The Data Team will review it. | |||||
| 25 | 732 contacts → | ||||
Partial evidence “ESA is a 100% employee-owned environmental consulting firm.” Source: RevenueBase Database · checked Sep 28, 2026Thanks. The Data Team will review it. | |||||
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: hydrological consulting firms. 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 hydrological consulting firms.
- Partial evidence
- Its own public description names part of hydrological consulting firms, so it works in or next to the category without describing itself that way.
- Indirect evidence
- The description shown does not name hydrological consulting firms. 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 7,057 hydrological consulting firms worldwide
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Hydrological consulting firms worldwide at a glance
As of Sep 28, 2026Companies by employee count
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 hydrological 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.
- Coverage
- Every country. Country and city lists for hydrological consulting firms are linked below.
- What qualifies
- Companies worldwide whose own description of what they do matches “hydrological 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 hydrological 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 hydrological consulting firms, 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, 58,720 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 28, 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.
Hydrological consulting firms by location
34 lists · largest firstEvery Hydrological consulting firms list RevenueBase publishes, by country and city. Counts are matching companies in each list as of its own refresh date.
Countries
- Hydrological consulting firms based in the United States1,547
- Hydrological consulting firms based in France392
- Hydrological consulting firms based in Brazil386
- Hydrological consulting firms based in Canada346
- Hydrological consulting firms based in Australia340
- Hydrological consulting firms based in Germany283
- Hydrological consulting firms based in the United Kingdom262
- Hydrological consulting firms based in India194
- Hydrological consulting firms based in Chile181
- Hydrological consulting firms based in Spain179
- Hydrological consulting firms based in Italy161
- Hydrological consulting firms based in the Netherlands139
- Hydrological consulting firms based in South Africa137
- Hydrological consulting firms based in Colombia121
- Hydrological consulting firms based in Switzerland97
- Hydrological consulting firms based in Peru87
- Hydrological consulting firms based in Türkiye79
- Hydrological consulting firms based in Argentina64
- Hydrological consulting firms based in New Zealand54
- Hydrological consulting firms based in Austria51
- Hydrological consulting firms based in Sweden47
- Hydrological consulting firms based in Belgium38
- Hydrological consulting firms based in Portugal34
- Hydrological consulting firms based in Greece33
- Hydrological consulting firms based in Norway29
- Hydrological consulting firms based in Denmark28
Cities
- Hydrological consulting firms based in Belo Horizonte, Brazil60
- Hydrological consulting firms based in Santiago, Chile44
- Hydrological consulting firms based in Sao Paulo, Brazil40
- Hydrological consulting firms based in Sydney, Australia38
- Hydrological consulting firms based in Calgary, Canada35
- Hydrological consulting firms based in Houston, United States34
- Hydrological consulting firms based in Madrid, Spain33
- Hydrological consulting firms based in Ankara, Türkiye28
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 hydrological 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 hydrological consulting firms are there worldwide?
RevenueBase identified 7,057 hydrological consulting firms 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?
Tetra Tech, headquartered in Pasadena, tops this list with the largest team on record.
Which country has the most hydrological consulting firms?
The United States leads with 1,547 companies, followed by France (392) and Brazil (386). Every hydrological consulting firms list by country and city is linked on this page.
Which city has the most hydrological consulting firms?
Belo Horizonte leads with 60 headquartered companies, followed by Tehran (53) and Santiago (44).
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 58,720 verified decision-maker contacts tracked across these 7,057 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 28, 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.