Company lists · Data refreshed September 2026
Top 25 Wastewater system design engineers based in the United States
RevenueBase identified 186 wastewater system design engineers headquartered in the United States as of September 2026 and tracks 3,939 professional contacts across them, including 2,162 with verified work emails. Houston is the largest hub.
This list covers wastewater system design engineers 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.
The 25 largest wastewater system design engineers based in the United States
Ranked by team size| # | Company | Contacts | |||
|---|---|---|---|---|---|
| 1 | 1,718 contacts → | ||||
Strong evidence “For more than 90 years, Carollo Engineers has been dedicated exclusively to water and wastewater solutions.” Source: RevenueBase Database · checked Sep 22, 2026Thanks. The Data Team will review it. | |||||
| 2 | 315 contacts → | ||||
Partial 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, 2026Thanks. The Data Team will review it. | |||||
| 3 | 136 contacts → | ||||
Strong evidence “RH2 is an innovative, full-service engineering firm specializing in water and wastewater related projects.” Source: RevenueBase Database · checked Sep 22, 2026Thanks. The Data Team will review it. | |||||
| 4 | 135 contacts → | ||||
Partial evidence “Water Works Engineers is a leading civil and environmental engineering firm specializing in innovative and sustainable solutions for water infrastructure projects across the…” Source: RevenueBase Database · checked Sep 22, 2026Thanks. The Data Team will review it. | |||||
| 5 | 112 contacts → | ||||
Partial evidence “Over the past 45 years, GSE Construction has completed more than projects as a general engineering contractor.” Source: RevenueBase Database · checked Sep 22, 2026Thanks. The Data Team will review it. | |||||
| 6 | 101 contacts → | ||||
Strong evidence “Today, Jones & Henry Engineers, Ltd, continues to provide high quality consulting services in water, wastewater, storm water, and civil engineering to municipalities and…” Source: RevenueBase Database · checked Sep 22, 2026Thanks. The Data Team will review it. | |||||
| 7 | 79 contacts → | ||||
Partial evidence “The objective of A&S is to provide municipal engineering services, with focus on water districts, municipalities, and land development.” Source: RevenueBase Database · checked Sep 22, 2026Thanks. The Data Team will review it. | |||||
| 8 | 78 contacts → | ||||
Indirect evidence “Water: It’s a human thing.” Source: RevenueBase Database · checked Sep 22, 2026Thanks. The Data Team will review it. | |||||
| 9 | 54 contacts → | ||||
Strong evidence “AQUA Engineering (AQUA) is a civil engineering firm specializing in municipal engineering, water resources, water and wastewater treatment design, and environmental services.” Source: RevenueBase Database · checked Sep 22, 2026Thanks. The Data Team will review it. | |||||
| 10 | 47 contacts → | ||||
Strong evidence “NCS is an experienced water and wastewater engineering consulting firm with offices in Arizona, Maryland, Nevada, New Mexico and California.” Source: RevenueBase Database · checked Sep 22, 2026Thanks. The Data Team will review it. | |||||
| 11 | 31 contacts → | ||||
Strong evidence “ClearStream Environmental engineers high-performance water and wastewater treatment solutions for municipal and industrial applications.” Source: RevenueBase Database · checked Sep 22, 2026Thanks. The Data Team will review it. | |||||
| 12 | 30 contacts → | ||||
Indirect evidence “Practical Applications Inc.” Source: RevenueBase Database · checked Sep 22, 2026Thanks. The Data Team will review it. | |||||
| 13 | 30 contacts → | ||||
Strong evidence “Design Build Solutions for Wastewater Collection Systems and Treatment Facilities.” Source: RevenueBase Database · checked Sep 22, 2026Thanks. The Data Team will review it. | |||||
| 14 | 28 contacts → | ||||
Indirect evidence “Since 1992, Sawcross, Inc.” Source: RevenueBase Database · checked Sep 22, 2026Thanks. The Data Team will review it. | |||||
| 15 | 28 contacts → | ||||
Partial evidence “Environ-Civil Engineering, Ltd.” Source: RevenueBase Database · checked Sep 22, 2026Thanks. The Data Team will review it. | |||||
| 16 | 26 contacts → | ||||
Strong evidence “A leading provider of professional engineering services to public water and wastewater systems for over 90 years.” Source: RevenueBase Database · checked Sep 22, 2026Thanks. The Data Team will review it. | |||||
| 17 | 25 contacts → | ||||
Strong evidence “Baird Gilroy & Dixon, LLC is a full service electrical engineering firm specializing in Water and Wastewater projects from concept through construction.” Source: RevenueBase Database · checked Sep 22, 2026Thanks. The Data Team will review it. | |||||
| 18 | 24 contacts → | ||||
Strong evidence “Engineering consulting firm specializing in planning, design, and construction administration of water and wastewater infrastructure.” Source: RevenueBase Database · checked Sep 22, 2026Thanks. The Data Team will review it. | |||||
| 19 | 19 contacts → | ||||
Partial evidence “Civil Engineering Consultants, Inc.(CEC) is a Civil and Environmental Engineering firm serving the Atlanta, Georgia metropolitan area.” Source: RevenueBase Database · checked Sep 22, 2026Thanks. The Data Team will review it. | |||||
| 20 | 18 contacts → | ||||
Strong evidence “At Streamkey Inc, we specialize in custom engineered water and wastewater systems for a variety of commercial and residential applications.” Source: RevenueBase Database · checked Sep 22, 2026Thanks. The Data Team will review it. | |||||
| 21 | 18 contacts → | ||||
Strong evidence “Jones-Heroy & Associates is a civil engineering firm specializing in the water and wastewater industry with offices located in Austin, Dallas and Lampasas.” Source: RevenueBase Database · checked Sep 22, 2026Thanks. The Data Team will review it. | |||||
| 22 | 18 contacts → | ||||
Strong evidence “Water and Wastewater Solutions for Lasting Community Impact At Modern Engineering Solutions, we provide end-to-end services for water treatment, collection, and distribution…” Source: RevenueBase Database · checked Sep 22, 2026Thanks. The Data Team will review it. | |||||
| 23 | 17 contacts → | ||||
Partial evidence “Champlin Associates specializes in Municipal Water and Wastewater Pumps, Controls, Operations, Filtration, and Treatment.” Source: RevenueBase Database · checked Sep 22, 2026Thanks. The Data Team will review it. | |||||
| 24 | 17 contacts → | ||||
Partial evidence “Senior Civil and Environmental Engineer at Weber, Hayes and Associates.” Source: RevenueBase Database · checked Sep 22, 2026Thanks. The Data Team will review it. | |||||
| 25 | 17 contacts → | ||||
Partial evidence “We’re redefining what it means to partner with a consulting engineering firm.” Source: RevenueBase Database · checked Sep 22, 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: wastewater system design engineers. 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 wastewater system design engineers.
- Partial evidence
- Its own public description names part of wastewater system design engineers, so it works in or next to the category without describing itself that way.
- Indirect evidence
- The description shown does not name wastewater system design engineers. 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 186 wastewater system design engineers based in the United States
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Wastewater system design engineers based in the United States at a glance
As of Sep 22, 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 186 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 wastewater system design engineers, 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 “wastewater system design engineers”. 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 wastewater system design engineers), 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 wastewater system design engineers, 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, 2,162 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 wastewater system design engineers, 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 wastewater system design engineers are there based in the United States?
RevenueBase identified 186 wastewater system design engineers 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?
Carollo Engineers, headquartered in Walnut Creek, tops this list with the largest team on record.
Which city has the most wastewater system design engineers?
Houston leads with 6 headquartered companies, followed by Austin (5) and Phoenix (4).
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 2,162 verified decision-maker contacts tracked across these 186 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.
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