The companies listed in California primarily operate in environmental services, offering a range of consulting, engineering, and management solutions. These are mostly large, established firms, many of which are privately held or public agencies.
Key companies include Brown and Caldwell, specializing in water and environmental sectors; Carollo Engineers, focused exclusively on water-related engineering; Rain For Rent, providing temporary liquid handling solutions; and Recology, offering waste collection, recycling, and composting services. A notable pattern is the presence of several public agencies, such as the State Water Resources Control Board and Los Angeles County Sanitation Districts, indicating a significant public sector involvement in environmental management.
| # | Company | Employees | |||
|---|---|---|---|---|---|
| 1 |
Brown and Caldwellbrownandcaldwell.com
Privately-held environmental firm specializing in US water and environmental sectors Offering engineering, scientific, consulting, and construction services globally Passionate about innovation and service excellence |
2,556 | |||
| 2 |
Carollo Engineerscarollo.com
Specializing solely in water related engineering, we provide innovative solutions, unparalleled client service, and a collaborative working environment since 1933 |
1,803 | |||
| 3 |
Partner Engineering & Science, Inc.partneresi.com
National firm providing engineering, environmental, and energy consulting services, from due diligence to design, construction, maintenance, and compliance in various industries |
1,438 | |||
| 4 |
Rain For Rentrainforrent.com
Provider of temporary liquid handling solutions through pumps, tanks, filtration, and spill containment for flood relief, construction dewatering, sewer bypasses, and turnarounds. |
1,386 | |||
| 5 |
State Water Resources Control Boardwaterboards.ca.gov
The company works under the California Environmental Protection Agency to preserve, enhance, and restore water quality for environmental protection and public health |
1,377 | |||
| 6 |
Recologyrecology.com
Recology provides waste collection, recycling, and composting services in multiple states, prioritizing sustainability, employee ownership, and customer satisfaction |
1,306 | |||
| 7 |
SCS Engineersscsengineers.com
Environmental solutions provider with expertise in compliance, technology, consulting, engineering, construction, O&M, monitoring, and compliance for private and public sector clients |
1,278 | |||
| 8 |
Blackstone Consulting, Inc.blackstone-consulting.com
A minority-owned company providing environmental, security, facilities maintenance, staffing, and food service management services to national and international clients since 1991 |
1,091 | |||
| 9 |
Resource Innovationsresource-innovations.com
A women-led energy transformation focused on clean energy solutions, specializing in energy efficiency and guiding utilities through complex challenges |
1,072 | |||
| 10 |
Los Angeles County Sanitation Districtslacsd.org
The company provides wastewater and solid waste management services, converting waste into resources like reclaimed water, energy, and recycled materials |
997 | |||
| 11 |
California Department of Toxic Substances Controldtsc.ca.gov
Protecting California's people and environment from harmful effects of toxic substances by enforcing laws, reducing waste generation, and promoting chemically safer products |
919 | |||
| 12 | 850 | ||||
| 13 |
SCS Global Servicesscsglobalservices.com
Trusted leader in third-party environmental, sustainability, and food quality certification, auditing, testing, and standards development, driving practices for sustainable development worldwide |
762 | |||
| 14 |
Environmental Science Associatesesassoc.com
Employee-owned environmental consulting firm with expertise in planning, design, permitting, mitigation, restoration, and compliance for diverse projects across various regions |
746 | |||
| 15 |
South Coast Air Quality Management Districtaqmd.gov
Regulatory agency in Southern California working to improve air quality by controlling emissions from stationary sources and advocating for public health |
740 | |||
| 16 |
Athens Servicesathensservices.com
Family-owned waste collection & recycling company serving 275,000+ customers in greater Los Angeles area with focus on sustainability & community investment |
702 | |||
| 17 |
FCSfirstcarbonsolutions.com
Leading provider of environmental, sustainability, and compliance solutions with expertise in CEQA/NEPA, compliance, permitting, natural resources management, and more Join our team! |
613 | |||
| 18 | 582 | ||||
| 19 | 550 | ||||
| 20 |
JJ&S Environmental Servicesjjandsenvironmental.com
The company specializes in large-scale remodeling and emergency projects, particularly water or fire damage, with a focus on transparent pricing and accepting any project |
529 | |||
| 21 |
Rincon Consultantsrinconconsultants.com
Provides environmental sciences, planning, and engineering consulting services, offering solutions for environmental planning, biological resources, cultural resources, water, site assessment, and sustainability. |
524 | |||
| 22 |
Citizens' Climate Lobbycitizensclimatelobby.org
Educating and training individuals to lobby lawmakers for environmental causes; nonpartisan, nonprofit, grassroots organization |
491 | |||
| 23 |
Environmental Servicesenvirosvs.com
A multi-functional company offering inspection, remediation, and restoration services for indoor air quality issues, mold, allergens, and property-related problems |
448 | |||
| 24 |
AEI Consultantsaeiconsultants.com
A company offering building, environmental, land, and sustainability consulting services across North America, working with various players in real estate industry |
444 | |||
| 25 |
Bay Area Air Quality Management Districtbaaqmd.gov
Regional agency regulating air pollution in San Francisco Bay Area, promoting healthy breathing environment through science-based policies, leadership, collaboration, and equity |
387 | |||
Want more companies than this list?This page shows the largest ones only. Connect to Tamtam to see every company that matches, filter by size, industry or growth, and reach their decision-makers. | |||||
| 26 |
American Leak Detectionamericanleakdetection.com
Specializing in non-destructive detection, the company accurately and efficiently identifies hidden water, sewer, and gas leaks in various types of buildings worldwide |
386 | |||
| 27 |
Burrtec Wasteburrtec.com
A leading waste management company in California, providing top-notch service to industrial, commercial, municipal, and residential customers for over 50 years |
350 | |||
| 28 |
Golden Gate National Parks Conservancyparksconservancy.org
Nonprofit partner supporting the Golden Gate National Recreation Area through collaboration, awareness building, volunteer opportunities, and education, connecting people to parks |
346 | |||
| 29 |
CR&R Incorporatedcrrwasteservices.com
Innovative environmental recycling collection company serving millions of people and thousands of businesses in Southern California counties |
345 | |||
| 30 |
Picarropicarro.com
This company designs and manufactures precision instruments for various applications, utilizing cavity ring-down spectroscopy technology for global deployment and reliability |
313 | |||
| 31 |
ACTenviro, a Republic Services Companyactenviro.com
An employee-owned environmental management company providing hazardous waste management, recycling, treatment, and compliance services throughout the western United States |
302 | |||
| 32 |
3Degrees Group, Inc.3degreesinc.com
This company helps businesses achieve renewable energy and decarbonization goals by providing sustainability consulting and environmental market solutions worldwide |
292 | |||
| 33 |
GreenWastegreenwaste.com
An industry leader in recycling and waste diversion, specializing in material collection, processing, and sales with a focus on environmental sustainability and innovation |
222 | |||
| 34 |
California Coastal Commissioncoastal.ca.gov
The company is dedicated to safeguarding and improving California's coast and ocean through sustainable development, science-based regulation, public engagement, education, and coordination |
193 | |||
| 35 |
TreePeopletreepeople.org
This organization in Los Angeles focuses on utilizing trees and nature-based solutions to address climate change impacts, engaging communities for a greener city |
170 | |||
| 36 |
Ascentascent.inc
A collaborative company solving unprecedented challenges through planning, design, science, and kindness with offices across multiple cities and a focus on a caring work environment |
169 | |||
| 37 |
ECORP Consulting, Inc.ecorpconsulting.com
Environmental consulting firm offering full service capability for regulatory compliance, environmental planning, permit negotiation, and mitigation design to public and private land owners since 1987 |
166 | |||
| 38 |
Terraphase Engineering Inc.terraphase.com
Environmental and engineering consulting firm providing cost-effective solutions, technical expertise, and regulatory compliance to achieve clients' project goals |
165 | |||
| 39 |
Geo-Logic Associates, Inc.geo-logic.com
Employee-owned consulting firm offering multidisciplinary services in engineering, geology, hydrogeology, environmental compliance, and water resources for various projects across 27 US locations |
163 | |||
| 40 |
Beewisebeewise.ag
This company designs modern beehives to prioritize the well-being and longevity of bees, providing a healthier and more natural living environment |
160 | |||
| 41 |
SEIseiinc.org
Environmental nonprofit building leaders for sustainability solutions through programs in schools, communities, and businesses to create thriving, resilient communities |
159 | |||
| 42 |
Heirloomheirloomcarbon.com
Developing cost-effective DAC technology to remove CO2 from the atmosphere quickly First facility in North America capturing CO2 for major clients like Microsoft |
158 | |||
| 43 |
ArborWorks, LLCarborworksinc.com
Vegetation management and wildfire hazard mitigation services for various sectors, accredited by industry organizations, with expertise in tree care and forestry |
152 | |||
| 44 |
Alliance Environmental Group, LLC.alliance-enviro.com
A leading environmental specialist in California, offering services including asbestos, mold, and lead removal, air duct cleaning, and trauma scene cleanup |
150 | |||
| 45 |
Verdani Partnersverdani.com
A sustainability consulting firm specializing in greening existing buildings, LEED certification, and corporate sustainability strategies, empowering organizations to create regenerative buildings and communities |
82 | |||
| 46 |
Partner Energyptrenergy.com
Provide energy efficiency engineering, sustainability, ESG consulting, project financing expertise, and support for renewable energy and incentive programs nationwide. |
57 | |||
| 47 |
Rubicon Carbonrubiconcarbon.com
A next-generation carbon solutions provider delivering at-scale decarbonization projects and enterprise-grade solutions for carbon credit purchases |
49 | |||
| 48 |
EnerPathenerpath.com
EnerPath helps businesses and communities save energy by offering a transparent, real-time delivery platform with proven products and services |
46 | |||
| 49 |
AWRdatasdy.site
Environmental consulting firm specializing in resolving contamination and water resource issues for government, industry, and developers through a range of services Email for more information |
44 | |||
| 50 |
Eurofins Air Toxics, Inc.airtoxics.com
An ISO 17025 accredited air testing laboratory specializing in EPA, CARB, and ASTM methods, serving public and private sector clients |
32 | |||
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How this list is built
Every company on this list has a Tamtam company profile. The industry is the one the company gives on LinkedIn; categories such as SaaS or fintech are classified by Tamtam's AI from the company's website and LinkedIn page; and the headquarters city must match the company's own address. Companies are ranked by the number of employees on LinkedIn, and the list is refreshed every night. Classifications can be wrong, so treat the list as a starting point rather than an official ranking. Last updated Nov 14, 2026.
More company lists in California
- The largest companies in California 15,258
- Multinational companies in California 2,587
- SaaS companies in California 1,854
- Software Development companies in California 1,649
- AI companies in California 1,296
- Companies with in-house R&D in California 1,272
- Manufacturers in California 1,065
- Hardware manufacturers in California 984
- IT Services and IT Consulting companies in California 968
- Education providers in California 950
- Subscription businesses in California 939
- Venture capital and private equity firms in California 917
- Professional services firms in California 880
- Companies with a mobile app in California 827
- Retail chains in California 802
- IT services companies in California 796
- Venture Capital and Private Equity Principals companies in California 731
- Financial services firms in California 711
- Financial Services companies in California 642
- Healthcare providers in California 569
- AI-native companies in California 561
- Hospitals and Health Care companies in California 555
- Consulting firms in California 551
- Public sector organisations in California 536