Company lists · Data refreshed September 2026

Top 25 Environmental engineering firms based in Houston, United States

Name: Environmental engineering firms based in Houston, United States
Creator: RevenueBase
License: https://creativecommons.org/licenses/by/4.0/

Compiled by the RevenueBase Data Team Data refreshed Sep 16, 2026 138 companies tracked

RevenueBase identified 138 environmental engineering firms headquartered in Houston, United States as of September 2026 and tracks 8,928 professional contacts across them, including 4,915 with verified work emails. Houston is the largest hub.

This list covers environmental engineering firms headquartered in Houston, 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 16, 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 16, 2026 86% judged on-target in blind review

138Companies

8,928Contacts tracked

4,915Verified emails

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The 25 largest environmental engineering firms based in Houston, United States

Ranked by team size

Top 25 of 138 environmental engineering firms based in Houston, United States, ranked by team size, largest first. Data refreshed Sep 16, 2026. RevenueBase Smart Search rates how each company's information relates to environmental engineering firms: 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	LJA	Indirect evidence	Houston, TX, United StatesHQ checked Sep 16, 2026	1,001-5,000	1,932 contacts →
	Indirect evidence “Employee-Owned.” Source: RevenueBase Database · checked Sep 16, 2026
2	Walter P Moore	Indirect evidence	Houston, TX, United StatesHQ checked Sep 16, 2026	1,001-5,000	1,298 contacts →
	Indirect evidence “Welcome to Walter P Moore!” Source: RevenueBase Database · checked Sep 16, 2026
3	Bge, INC	Indirect evidence	Houston, TX, United StatesHQ checked Sep 16, 2026	1,001-5,000	1,112 contacts →
	Indirect evidence “Ranked No.” Source: RevenueBase Database · checked Sep 16, 2026
4	Quiddity	Partial evidence	Houston, TX, United StatesHQ checked Sep 16, 2026	501-1,000	683 contacts →
	Partial evidence “Quiddity is an award-winning, full-service civil engineering, planning, surveying, and consulting firm providing innovative solutions for public infrastructure and private…” Source: RevenueBase Database · checked Sep 16, 2026
5	Lockwood, Andrews & Newnam, Inc. LAN	Partial evidence	Houston, TX, United StatesHQ checked Sep 16, 2026	201-500	461 contacts →
	Partial evidence “Lockwood, Andrews & Newnam, Inc.(LAN) is a full-service consulting firm offering planning, engineering and program management services.” Source: RevenueBase Database · checked Sep 16, 2026
6	Tolunay-Wong Engineers, INC	Partial evidence	Houston, TX, United StatesHQ checked Sep 16, 2026	201-500	260 contacts →
	Partial evidence “Founded in 1993, Tolunay-Wong Engineers, Inc.(TWE) is ranked as one of the Top 10 largest civil engineering firms in Houston.” Source: RevenueBase Database · checked Sep 16, 2026
7	GSI Environmental INC	Strong evidence	Houston, TX, United StatesHQ checked Sep 16, 2026	201-500	259 contacts →
	Strong evidence “GSI Environmental, Inc.(GSI), is an environmental engineering and science consulting firm committed to measuring, analyzing, and solving complex environmental problems around the…” Source: RevenueBase Database · checked Sep 16, 2026
8	Ehra Engineering	Partial evidence	Houston, TX, United StatesHQ checked Sep 16, 2026	201-500	247 contacts →
	Partial evidence “EHRA Engineering is a civil engineering, surveying, low impact developing, land planning, construction phase services, traffic, emergency management and landscape architecture…” Source: RevenueBase Database · checked Sep 16, 2026
9	HVJ Associates	Indirect evidence	Houston, TX, United StatesHQ checked Sep 16, 2026	51-200	199 contacts →
	Indirect evidence “Completing public infrastructure projects comes with tremendous pressure to serve the public while completing each project on-time and on-budget.” Source: RevenueBase Database · checked Sep 16, 2026
10	Shah Smith & Associates, INC	Partial evidence	Houston, TX, United StatesHQ checked Sep 16, 2026	51-200	134 contacts →
	Partial evidence “Shah Smith & Associates, Inc.(SSA) is a 120+ employee Mechanical, Electrical, and Plumbing (MEP) consulting engineering firm with offices in Houston, Austin & Dallas.” Source: RevenueBase Database · checked Sep 16, 2026
11	Edge Engineering And Science, LLC	Partial evidence	Houston, TX, United StatesHQ checked Sep 16, 2026	51-200	116 contacts →
	Partial evidence “Edge Engineering & Science, LLC (EDGE) is a privately owned professional services firm headquartered in Houston, Texas.” Source: RevenueBase Database · checked Sep 16, 2026
12	RG Miller Dccm	Partial evidence	Houston, TX, United StatesHQ checked Sep 16, 2026	51-200	111 contacts →
	Partial evidence “RG Miller \| DCCM is a Houston-based civil engineering firm providing a wide range of infrastructure services to both public and private sector clients in Texas.” Source: RevenueBase Database · checked Sep 16, 2026
13	S&b Infrastructure, LTD	Partial evidence	Houston, TX, United StatesHQ checked Sep 16, 2026	51-200	97 contacts →
	Partial evidence “S&B Infrastructure, Ltd.(S & BI) has been in existence since 1994 as part of S&B Holdings, Ltd,(one of the largest privately-owned engineering firms in the State of Texas).” Source: RevenueBase Database · checked Sep 16, 2026
14	Omega Engineers, INC	Partial evidence	Houston, TX, United StatesHQ checked Sep 16, 2026	51-200	79 contacts →
	Partial evidence “Founded in 1984, OMEGA is an engineering and construction management firm specializing in infrastructure, civil engineering, highway engineering, transportation planning, railway…” Source: RevenueBase Database · checked Sep 16, 2026
15	A&s Engineers, INC	Partial evidence	Houston, TX, United StatesHQ checked Sep 16, 2026	51-200	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 16, 2026
16	Civitas Engineering Group, INC	Partial evidence	Houston, TX, United StatesHQ checked Sep 16, 2026	51-200	65 contacts →
	Partial evidence “Civitas Engineering Group Inc.” Source: RevenueBase Database · checked Sep 16, 2026
17	Idcus INC	Partial evidence	Houston, TX, United StatesHQ checked Sep 16, 2026	51-200	64 contacts →
	Partial evidence “Infrastructure Consulting & Engineering, LLC (formerly IDCUS Inc.), is a leading Texas-based professional services, civil engineering, and consulting firm specializing in public…” Source: RevenueBase Database · checked Sep 16, 2026
18	Aarc Environmental	Partial evidence	Houston, TX, United StatesHQ checked Sep 16, 2026	51-200	63 contacts →
	Partial evidence “As a leader in the environmental compliance services industry, AARC does more than just meeting the needs of clients today.” Source: RevenueBase Database · checked Sep 16, 2026
19	Sage ATC Environmental Consulting	Partial evidence	Houston, TX, United StatesHQ checked Sep 16, 2026	201-500	63 contacts →
	Partial evidence “Sage ATC Environmental Consulting is now Atlas.” Source: RevenueBase Database · checked Sep 16, 2026
20	Spirit Environmental Montrose Environmental Group	Indirect evidence	Houston, TX, United StatesHQ checked Sep 16, 2026	51-200	54 contacts →
	Indirect evidence “In July of 2024, Spirit was acquired by Onterris.” Source: RevenueBase Database · checked Sep 16, 2026
21	JDM Group Company, LLC	Indirect evidence	Houston, TX, United StatesHQ checked Sep 16, 2026	51-200	51 contacts →
	Indirect evidence “Since 2008… JDM Group Company has been providing consulting and construction services for both public and private sector clients in a cost effective, timely, and innovative manner.” Source: RevenueBase Database · checked Sep 16, 2026
22	RPT Alliance LLC	Indirect evidence	Houston, TX, United StatesHQ checked Sep 16, 2026	11-50	43 contacts →
	Indirect evidence “As of December 8, 2025, RTP Alliance has been acquired by by Bowman.” Source: RevenueBase Database · checked Sep 16, 2026
23	RSB Environmental, An Alliance Technical Group Company	Strong evidence	Houston, TX, United StatesHQ checked Sep 16, 2026	11-50	38 contacts →
	Strong evidence “RSB Environmental, an Alliance Technical Group company, is a full-service environmental engineering consulting firm, specializing in environmental health and safety services and…” Source: RevenueBase Database · checked Sep 16, 2026
24	Vogler & Spencer Engineering, INC	Partial evidence	Houston, TX, United StatesHQ checked Sep 16, 2026	11-50	35 contacts →
	Partial evidence “Vogler & Spencer Engineering provides civil engineering consulting services to public and private clients in the Houston area and surrounding counties.” Source: RevenueBase Database · checked Sep 16, 2026
25	Phase Engineering, LLC	Strong evidence	Houston, TX, United StatesHQ checked Sep 16, 2026	11-50	34 contacts →
	Strong evidence “Phase Engineering, LLC, was founded in 1993 and is a leading engineering and environmental consulting firm, serving clients nationwide to deliver trusted environmental solutions.” Source: RevenueBase Database · checked Sep 16, 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: environmental engineering 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 environmental engineering firms.
Partial evidence: Its own public description names part of environmental engineering firms, so it works in or next to the category without describing itself that way.
Indirect evidence: The description shown does not name environmental engineering 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 138 environmental engineering firms based in Houston, United States

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Environmental engineering firms based in Houston, United States at a glance

As of Sep 16, 2026

55.1%Verified-email coverage

64.7Average contacts per company

11-50Median size (employees)

100.0%Largest-city concentration · Houston

Sep 16, 2026Page data refreshed

Companies by employee count

1-10

11-50

51-200

201-500

501-1,000

1,001-5,000

Email recency for this list is measured across the whole United States list rather than for Houston, so it is reported there. Company counts and contact totals on this page are exact for Houston, over 138 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 environmental engineering 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.
What qualifies: Companies headquartered in Houston, United States whose own description of what they do matches “environmental engineering 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 environmental engineering 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 environmental engineering firms, and records with no verified work email. Companies headquartered outside Houston 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, 4,915 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 16, 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.

Environmental engineering firms by metro in the United States

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 environmental engineering 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 environmental engineering firms are there based in Houston, United States?

RevenueBase identified 138 environmental engineering firms headquartered in Houston, 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?

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

Which city has the most environmental engineering firms?

Houston leads with 138 headquartered companies, followed by New York (101) and Austin (73).

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 4,915 verified decision-maker contacts tracked across these 138 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 16, 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.