Company lists · Data refreshed September 2026
Top 25 Water resources engineering staffing companies based in the United States
RevenueBase identified 1,543 water resources engineering staffing companies headquartered in the United States as of September 2026 and tracks 90,289 professional contacts across them, including 40,024 with verified work emails. Houston is the largest hub.
This list covers water resources engineering staffing 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 29, 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.
The 25 largest water resources engineering staffing companies based in the United States
Ranked by team size| # | Company | Contacts | |||
|---|---|---|---|---|---|
| 1 | 12,999 contacts → | ||||
Strong 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 29, 2026Thanks. The Data Team will review it. | |||||
| 2 | 7,527 contacts → | ||||
Partial evidence “CDM Smith is shaping what’s next, now, with world class solutions in water, environment, transportation and energy to public and private clients worldwide.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 3 | 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 29, 2026Thanks. The Data Team will review it. | |||||
| 4 | 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 29, 2026Thanks. The Data Team will review it. | |||||
| 5 | 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 29, 2026Thanks. The Data Team will review it. | |||||
| 6 | 2,145 contacts → | ||||
Indirect 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 29, 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 29, 2026Thanks. The Data Team will review it. | |||||
| 8 | 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 29, 2026Thanks. The Data Team will review it. | |||||
| 9 | 1,604 contacts → | ||||
Indirect evidence Source: RevenueBase Database · checked Sep 29, 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 29, 2026Thanks. The Data Team will review it. | |||||
| 11 | 1,234 contacts → | ||||
Partial evidence “Let us make construction staffing work for you.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 12 | 1,187 contacts → | ||||
Strong evidence “TRS Staffing Solutions is a world leading engineering recruitment agency specialising in the recruitment and supply of professional, engineering, technical and field talent.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 13 | 1,137 contacts → | ||||
Indirect evidence “Who is Apex?” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 14 | 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 29, 2026Thanks. The Data Team will review it. | |||||
| 15 | 1,060 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 29, 2026Thanks. The Data Team will review it. | |||||
| 16 | 1,031 contacts → | ||||
Indirect evidence “Since its founding in 1976 in Portland, Oregon, DEA has become a recognized leader for progressive and sustainable design and management solutions for complex transportation, land…” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 17 | 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 29, 2026Thanks. The Data Team will review it. | |||||
| 18 | 795 contacts → | ||||
Partial evidence “Dudek is an environmental, planning, and engineering consulting firm.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 19 | 762 contacts → | ||||
Indirect evidence “This page is now closed.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 20 | 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 29, 2026Thanks. The Data Team will review it. | |||||
| 21 | 618 contacts → | ||||
Indirect evidence “HireQuest Direct specializes in day labor, general labor, disaster recovery, skilled labor, janitorial, site clean-up, composite crew, demolition, administrative, hospitality…” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 22 | 591 contacts → | ||||
Partial evidence “Neel-Schaffer is a multi-disciplined engineering, planning and construction management firm that was founded in 1983 and today is one of the largest private, employee-owned…” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 23 | 578 contacts → | ||||
Strong evidence “For over 100 years, Kennedy Jenks has provided engineering and scientific solutions for innovative water and environmental projects.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 24 | 547 contacts → | ||||
Indirect evidence “For more than 60 years, it has been the quality of our people that defines the DOWL difference.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 25 | 516 contacts → | ||||
Partial evidence “T&M Associates is a leading engineering and technical services firm focused on innovative solutions that advance our clients’ goals and sustain communities.” Source: RevenueBase Database · checked Sep 29, 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: water resources engineering staffing 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 engineering staffing companies.
- Partial evidence
- Its own public description names part of water resources engineering staffing 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 engineering staffing 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 1,543 water resources engineering staffing companies based in the United States
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Water resources engineering staffing companies based in the United States at a glance
As of Sep 29, 2026Companies by employee count
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 1,543 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 engineering staffing 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 engineering staffing 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 engineering staffing 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 engineering staffing 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, 40,024 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 29, 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 engineering staffing 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 water resources engineering staffing 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 engineering staffing companies are there based in the United States?
RevenueBase identified 1,543 water resources engineering staffing 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 engineering staffing companies?
Houston leads with 48 headquartered companies, followed by Austin (24) and Portland (19).
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 40,024 verified decision-maker contacts tracked across these 1,543 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 29, 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.
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