What GSI Environmental Inc. does

GSI Environmental Inc. is a privately held, Houston-headquartered environmental engineering and science consulting firm founded in 1986. Operating with approximately 261 employees across U.S. offices in Houston, Emeryville, Chico, Irvine, Granby, and Seattle, the firm serves six primary verticals — Industrial, Water, Energy/Minerals, Real Estate, Government, and Legal — with multidisciplinary services spanning groundwater modeling, site investigation and remediation, PFAS and emerging contaminants, toxicology and risk assessment, water resources, litigation support, and sustainability and climate advisory. Select clients include Tampa Bay Water, the U.S. Department of Defense, the U.S. Environmental Protection Agency, California High-Speed Rail Authority, and the cities of Santa Monica, Sacramento, and Irvine, with international project work across more than 40 countries.

The firm has built a substantial proprietary software portfolio that complements its consulting practice, including BIOSCREEN and BIOChlor (natural attenuation decision support), REMChlor-MD (chlorinated solvent management), MODFLOW-USG and its USG-Transport companion (unstructured-grid groundwater flow and transport), MAROS Optimization (monitoring network design), the Mann-Kendall Toolkit (trend analysis), BIOPLUME III, Soil Attenuation Models, and the Fish Advisory Calculator. Several of these tools originated under SERDP/ESTCP federal research programs and are widely used in EPA, DoD, and state agency remediation workflows. The firm maintains a GSA Schedule contract for federal services and participates in the Interstate Technology & Regulatory Council (ITRC).

GSI generates revenue primarily through professional services engagements under a sales-led, direct-engagement GTM model, with additional recurring and one-time revenue from proprietary software licensing (sold through authorized reseller FastSpring) and from training programs such as the Texas Risk Reduction Program (TRRP) course offered in partnership with the Texas Association of Environmental Professionals. The firm is ranked #9 on Zweig Group's 2026 Hot Firm List and operates with no disclosed institutional, private equity, or parent-company ownership.

Name

GSI Environmental Inc.

Legal name

GSI Environmental Inc.

Website

https://gsienv.com

Company type

Private

Founded year

1986

Operating status

Operating

Headcount range

251–500 employees

Short description

GSI Environmental Inc. is a privately held, Houston-based environmental engineering and science consulting firm serving government, industrial, legal, real estate, water, and energy/minerals clients with site investigation, remediation, risk assessment, water resources, PFAS, and climate services, supported by proprietary groundwater modeling software.

Ownership category

akta.pro rank

Headquarters

HQ city

Houston

HQ country

United States

HQ region

North America

Offices6 records

Markets served

GTM type

B2B

Offering type

Services

Cost components

Personnel, Operations, Technology or R&D, Marketing or Sales, Infrastructure

Revenue model

1. Environmental Consulting Services: Professional consulting services for environmental management, risk assessment, site investigation, remediation design, litigation support, and regulatory compliance across multiple sectors including industrial, government, legal, real estate, water, and energy/minerals.
2. Software Products: Sale of proprietary environmental software tools including groundwater modeling, fate and transport, and decision support tools. Purchases are processed through authorized reseller FastSpring.
3. Training Programs: Professional training courses such as the TRRP Training Program (Texas Risk Reduction Program) offered in partnership with Texas Association of Environmental Professionals (TAEP).

Pricing tiers

Go-to-market motion1 record

Distribution channels3 records

Marketing channels5 records

Core offering

GSI Environmental Inc. is an environmental engineering and science consulting firm that sells project-based environmental services (site investigation, remediation, water resources, risk assessment, regulatory support, sustainability/ESG, litigation support, due diligence) to government, industrial, legal and real estate clients. It also develops, sells and licenses a portfolio of proprietary groundwater, soil and fate-and-transport modeling software (BIOSCREEN, BIOChlor, REMChlor-MD, MAROS, Mann-Kendall Toolkit, MODFLOW-USG, BIOPLUME III, Fate 5, SAM, Fish Advisory Calculator) and delivers paid TRRP training programs.

Product overview

GSI Environmental Inc. is an environmental engineering and science consulting firm that offers a combination of professional consulting services and proprietary software tools. The core offering consists of specialized environmental consulting across areas including water resources, groundwater modeling, site investigation and remediation, PFAS and emerging contaminants, toxicology and risk assessment, and sustainability/climate services. Supporting the consulting practice, GSI has developed a portfolio of specialized software tools including BIOSCREEN and BIOChlor (natural attenuation decision support), REMChlor-MD (chlorinated solvent management), Mann-Kendall Toolkit (statistical trend analysis), MAROS Optimization (monitoring network optimization), and USG-Transport (groundwater transport modeling). Additional offerings include the Fish Advisory Calculator for public health assessments and TRRP Training for regulatory compliance education. The firm also provides client portals such as the Stormwater Portal for ongoing project management.

Differentiator

Problem solved

Functional benefit

Products and services

• Environmental Consulting Services

Quantifiable outcome

• Reduced overall cost of cleanup at impacted sites through easy-to-use, adaptable proprietary methods
• +2 more outcomes

Named customers11 records

Segments6 records

Ideal customer profiles5 records

Technology focussed Yes

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

Integration1 record

Feature10 records

Partnerships

One partnership is on record.

• Engineers Without Borders USAminorStrategic or Co-development Partner · 1 January 2026GSI is partnering with Engineers Without Borders USA to support a critical water project in Peru. The project will help improve water storage and reliability for the Q'ero Anexo Chua Chua community in the high Andes, where families depend on water for agriculture, livestock, and daily life.

Scale indicators7 records

Recent moves5 records

Expansion highlights5 records

Broad incumbents

• WSP: Global engineering professional services firm whose environment practice (built around Golder Associates) competes directly with GSI in site assessment, remediation, and water resources consulting.
• Tetra Tech: Large, publicly traded environmental, water, and sustainable infrastructure consulting firm with deep federal, water utility, and remediation practices that overlap directly with GSI's groundwater, site investigation, and PFAS service lines.
• AECOM: Global infrastructure consulting firm with a major environment practice covering site investigation, remediation, water resources, and climate services, competing for the same federal and industrial clients as GSI at significantly greater scale.
• Arcadis: Global design and consultancy firm with a substantial environment and water division offering remediation, risk assessment, and climate advisory services comparable to GSI's portfolio.
• Brown and Caldwell: Environmental engineering and consulting firm focused on water and wastewater utilities with adjacent groundwater, remediation, and stormwater capabilities that overlap with GSI's water resources practice.
• Jacobs Solutions: Major professional services firm with extensive environmental, water, and federal (DoD/EPA) practices; competes with GSI on large IDIQ remediation, groundwater modeling, and PFAS programs.

Direct peers

• Anchor QEA: Environmental science and engineering consulting firm specializing in sediment remediation, water resources, and ecosystem restoration, with similar scale and technical positioning to GSI.
• SLR Consulting: Global environmental and advisory consultancy with strong remediation, water, and PFAS practices serving industrial and government clients, closely comparable to GSI in scale and service mix.
• Haley & Aldrich: Privately held environmental and geotechnical engineering firm focused on site investigation, remediation, and risk-based decision making for industrial and real estate clients, highly comparable in size and specialization to GSI.
• ERM (Environmental Resources Management): Pure-play global environmental, health, safety, and sustainability consultancy serving industrial, energy, and financial clients with site investigation, remediation, and ESG services that closely mirror GSI's core offerings.

Market position

Strengths4 records

Weaknesses4 records

Competitive moat4 records

Key risks6 records

Key highlights6 records

Customer concentration

• YouTubeyoutube.com/channel/UCHfe41c67XLRS8fUZvmcxLw
• LinkedInlinkedin.com/company/gsienvironmental

Revenue estimate

Valuation estimate

Number of profiles

Profiles7 records

Funding overview

Funding rounds

Investors

Funding detail is available on the Subscription and Enterprise plan.Contact sales →

M&A

Investments

M&A and investment is available on the Subscription and Enterprise plan.Contact sales →

Frequently asked questions about GSI Environmental Inc.