Top Environmental Consulting Firms in 2026

An environmental consulting firm helps public and private organisations measure, manage, and reduce their environmental impact across air, water, land, biodiversity, climate, and waste by combining science, engineering, and policy expertise to deliver permitting, remediation, impact assessment, ESG strategy, and climate-resilience advisory.

What environmental consulting firms do and why they matter

Environmental consulting firms help public and private clients understand, manage, and reduce their environmental impacts across air, water, land, waste, biodiversity, and climate. They combine science, engineering, and policy expertise to support impact assessment, permitting, remediation, compliance, ESG and sustainability integration, and resilience planning.

The global environmental consulting market is led by large integrated firms such as AECOM, WSP, Jacobs, Tetra Tech, Stantec, Arcadis, ERM, and Ramboll, with a substantial tier of regional and specialist firms behind them. A newer generation of pure-play sustainability advisors and digital-forward consultancies Anthesis, RSK, Montrose, Cadmus, and WayCarbon is scaling rapidly on the back of climate, ESG, and PFAS demand.

What is reshaping the market in 2026

Five forces are driving the 2026 environmental consulting market and explaining why some firms are growing faster than others.

1. The PFAS regulatory wave is now multi-year and multi-billion dollar.

The US EPA’s April 2024 drinking-water standard for six PFAS compounds and the July 2024 CERCLA hazardous-substance designation for PFOA and PFOS created a sustained remediation, testing, and litigation-support pipeline that is flowing through 2026 budgets. In May 2025 EPA announced it would keep the PFOA and PFOS drinking-water standards but reconsider the rules for the four other PFAS compounds narrowing but not eliminating the regulatory wave. Firms with deep PFAS practices Tetra Tech, Jacobs, Montrose, AECOM, GHD remain the clearest beneficiaries.

2. CSRD is real but reshaped, and IFRS S1/S2 is going global.

The first wave of EU CSRD sustainability reports landed in early 2025. The European Commission’s February 2025 Omnibus simplification proposal then narrowed the scope to companies with over 1,000 employees and €450M+ turnover, and the Council’s April 2025 “Stop-the-Clock” directive postponed second- and third-wave reporting by two years so most mid-cap reporting now falls in 2028 rather than 2026. The final Omnibus directive was adopted by the EU Council on 24 February 2026. Outside Europe, IFRS S1/S2 is being adopted or aligned to in the UK, Japan, Australia, Singapore, and Malaysia, broadening the disclosure-advisory market well beyond CSRD.

3. US ESG retrenchment has shifted vocabulary, not demand.

On 27 March 2025 the SEC voted to end its defence of the climate disclosure rule (the rule itself remains nominally on the books pending litigation in the Eighth Circuit), and US federal sustainability programmes have been scaled back. California SB 253 remains in force with a first reporting deadline of 10 August 2026; SB 261 was paused by a Ninth Circuit injunction in November 2025 pending appeal. Many large US corporates have quietly rebranded “ESG” practices as “sustainability”, “climate transition”, or “decarbonisation”, but the underlying advisory pipeline driven by investors, supply-chain customers, and international regulation remains intact.

4. Sector consolidation has accelerated.

Recent transactions are reshaping the competitive set: WSP closed its US$1.78B (~CAD 2.44B) acquisition of Power Engineers in October 2024; Jacobs spun off its Critical Mission Solutions and Cyber & Intelligence businesses as Amentum in September 2024 and in March 2026 completed the acquisition of the remaining stake in PA Consulting (~US$1.6B); Stantec acquired Morrison Hershfield in early 2024; Carlyle Group acquired a majority stake in Anthesis in June 2023; Ares Management acquired SLR Consulting from Charterhouse Capital Partners in 2022; and RSK has continued its rolling acquisition strategy. The result is a clearer separation between focused environmental and water firms (Jacobs, Tetra Tech) and broader infrastructure firms (AECOM, WSP, Stantec).

5. Proprietary digital tooling is starting to differentiate firms.

Emissions monitoring, supply-chain ESG screening, and environmental-licensing workflows are increasingly delivered through software rather than spreadsheets. Firms with proprietary platforms Anthesis (RiskHorizon, SCATTER, Vastum), WayCarbon (CLIMAS, MOVE, LICENTIA), Montrose (data analytics) are competing on a different axis from the pure consulting firms.

How we ranked these firms

The order below reflects a weighted blend of six factors, with no single factor overriding the others:

1. Scale of environmental services revenue and headcount.
2. Recognition in the established industry rankings: ENR Top 200 Environmental Firms, Environment Analyst Top 100, and the Verdantix Green Quadrant for sustainability consulting.
3. Depth of capability in 2026-priority areas: PFAS, CSRD and ISSB disclosure, climate adaptation, and decarbonisation.
4. Geographic reach with explicit weight given to firms with credible presence outside North America and Europe.
5. Distinctive specialist capability that competitors cannot easily replicate.
6. Growth momentum into 2026 acquisitions, capital backing, and market share trajectory.

Tier 1 firms (1–6) are the global integrators with multi-billion-dollar environmental and infrastructure revenue. Tier 2 firms (7–15) are major regional and specialist global players with distinct capability angles. Tier 3 firms (16–19) are specialist platforms and emerging firms where the right mandate can produce sharper expertise than a bigger competitor would offer.

Quick comparison of established global leaders

Tier 1: Global integrators

Multi-billion-dollar firms that combine deep environmental practices with infrastructure, water, and engineering capability at global scale.

1. AECOM

Headquarters: Dallas, Texas, USA | FY2024 revenue: ~US$16.2B | Employees: ~51,000

AECOM is the world’s largest infrastructure consulting firm and has held the #1 spot on ENR’s Top 200 Environmental Firms list for several consecutive years. It delivers engineering, environmental, water, and programme-management services across transport, buildings, water, and energy markets.

Key capabilities:

• Environmental impact assessment, permitting, remediation, and water-resources management.
• Climate-resilience, adaptation, and nature-based solutions integrated with capital infrastructure projects.
• Multi-disciplinary design and programme-management capability for federal and large-capex programmes.

Industries served:

• US federal agencies (USACE, DOD, EPA, GSA) and state and local governments.
• Transport, water utilities, energy, and industrial clients globally.

What sets it apart: Unmatched US federal programme-management capability USACE IDIQs, DOD environmental restoration, and Stafford Act post-disaster work that no European pure-play can replicate.

Watch out for: ESG strategy and corporate sustainability advisory is much shallower than its engineering depth; for board-level climate work, clients pair AECOM with ERM or a Big Four practice.

Best for: Federal agencies and large infrastructure owners with complex permitting, remediation, and multi-year capital programmes.

2. WSP Global

Headquarters: Montreal, Canada | FY2024 revenue: ~CAD 16.2B | Employees: ~73,000

WSP is one of the world’s largest professional-services firms and a perennial leader in environmental and sustainability consulting. Verdantix, ENR, and Environment Analyst all consistently rank WSP in the top tier.

Key capabilities:

• Environmental planning, EIA, permitting, ecology, and contamination assessment.
• Climate-risk assessments, decarbonisation pathways, and resilience planning for cities and infrastructure.
• Power, transport, water, and building-engineering integration with environmental services.

Industries served:

• Cities, regional governments, and utilities.
• Transport agencies, real estate, and private infrastructure owners.

What sets it apart: The October 2024 close of the Power Engineers acquisition (US$1.78B / approximately CAD 2.44B) made WSP the largest power-sector consultancy in North America, embedding environmental siting and permitting directly into transmission and generation pipelines a structural advantage as grid build-out accelerates.

Watch out for: Pure ESG strategy bench is shallower than ERM’s; corporate transition and CSRD assurance work is often outsourced or subcontracted.

Best for: Infrastructure and utility clients wanting environmental services integrated with engineering at global scale, especially in power and transport.

3. Jacobs Solutions

Headquarters: Dallas, Texas, USA | FY2024 revenue: ~US$11.5B | Employees: ~45,000

Jacobs is one of the world’s leading engineering and professional-services firms, with major water, remediation, and climate-resilience practices. The September 2024 spin-off of its government services arm (now Amentum, formed via Reverse Morris Trust with the Critical Mission Solutions and parts of Divergent Solutions businesses) refocused Jacobs around environment, water, and infrastructure. In January 2026 Jacobs announced it would acquire the remaining stake in PA Consulting (its London-headquartered innovation and transformation consultancy) for £1.216 billion (~US$1.6 billion); the deal closed March 20, 2026.

Key capabilities:

• Environmental planning, remediation, and hazardous-waste management.
• Water and wastewater engineering, including treatment, distribution, and PFAS solutions.
• Climate-resilience, coastal adaptation, and nature-based solutions integrated into infrastructure design.

Industries served:

• Water and wastewater utilities, port authorities, transport agencies.
• Federal and state agencies and industrial and energy clients.

What sets it apart: Post-Amentum, Jacobs is a leaner, more concentrated environmental and water firm with a sharper investment story around water, decarbonisation, and resilience, and now full ownership of PA Consulting providing strategy and digital-transformation capability alongside engineering delivery.

Watch out for: Portfolio reshaping continues into 2026; the PA Consulting full-acquisition integration is mid-flight and some long-standing federal client teams have moved with the Amentum spin-off.

Best for: Water utilities, port authorities, and infrastructure clients needing deep technical capacity on resilience, PFAS, and large remediation.

4. Tetra Tech

Headquarters: Pasadena, California, USA | FY2024 revenue: ~US$5.2B | Employees: ~30,000

Tetra Tech is a leading global consulting and engineering firm focused on water, environment, sustainable infrastructure, and renewable energy. It is consistently among the top three environmental firms on ENR’s list and is one of the most cited authorities on PFAS and emerging contaminants.

Key capabilities:

• Water-resources management, treatment, and PFAS detection and remediation.
• Environmental restoration, contaminated-site cleanup, and emerging-contaminant work.
• Environmental compliance, monitoring, and permitting for industrial and infrastructure projects.

Industries served:

• US federal and state agencies; international donor and development institutions.
• Utilities, mining, oil and gas, and industrial sectors.

What sets it apart: Probably the deepest dedicated PFAS practice of any consultancy worldwide, with proprietary detection and treatment technology and a backlog that has grown sharply since EPA’s April 2024 drinking-water standard and the CERCLA hazardous-substance designation effective July 2024.

Watch out for: USAID exposure (around 13% of revenue in FY2024, per the company’s 10-K) has been hit hard by the 2025 US foreign-aid retrenchment; the company has reported an 80% collapse in USAID and Department of State programme revenue and is rebuilding the backlog through domestic federal, state, and non-US donor work.

Best for: Water utilities, US state agencies, and industrial clients with significant contamination, PFAS, or emerging-contaminant exposure.

5. Stantec

Headquarters: Edmonton, Alberta, Canada | FY2024 revenue: ~CAD 5.9B (net revenue) | Employees: ~32,000

Stantec is a global design and consultancy firm that integrates environmental services with water, buildings, and community-development work. The 2024 acquisition of Morrison Hershfield deepened its building-science and building-envelope capability a niche that has become increasingly important as building-decarbonisation regulations bite.

Key capabilities:

• Environmental planning, ecosystem and biodiversity services, and contaminated-site management.
• Water, transportation, and community-development projects with embedded environmental components.
• Building science, retrofits, and embodied-carbon assessment for the built environment.

Industries served:

• Municipalities, regional authorities, and Indigenous communities.
• Energy, resources, and infrastructure developers.

What sets it apart: Unusual depth at the intersection of building science and environmental services building envelope, mechanical, and embodied carbon all sit alongside environmental compliance, which is rare among the top-tier firms.

Watch out for: Heavy North American exposure (around 70% of revenue); less of a natural first call for EMEA or Asia mandates.

Best for: Municipalities, utilities, and community-scale developers wanting integrated environmental, water, and urban-planning expertise, particularly in North America.

6. Arcadis

Headquarters: Amsterdam, Netherlands | FY2024 revenue: ~€5.0B (gross) / ~€3.9B (net) | Employees: ~36,000

Arcadis is a global design and consultancy firm for natural and built assets, with major capabilities in environment, water, infrastructure, and buildings. ENR Top 200 Environmental Firms and Environment Analyst both rank Arcadis as a leading global environmental services player, particularly strong in resilience.

Key capabilities:

• Site investigation, remediation, water quality, and ecological services.
• Climate-resilience, flood-risk management, and coastal protection for cities and infrastructure.
• Urban planning and sustainable mobility for cities.

Industries served:

• Cities, utilities, and infrastructure clients globally.
• Industrial sectors including chemicals, manufacturing, and real estate.

What sets it apart: Distinctive coastal-resilience and flood-risk track record New York Harbor storm-surge studies, Thames Estuary work, and Dutch Delta programme experience that maps directly onto the climate-adaptation funding wave intensifying across coastal cities through 2026.

Watch out for: Lower US federal exposure than AECOM or Jacobs; less of a natural prime for big federal IDIQs.

Best for: Urban and coastal infrastructure clients prioritising climate resilience, water, and remediation, especially in Europe and the Americas.

Tier 2: Major regional and specialist global firms

Major regional and specialist firms with distinct capability angles from pure-play sustainability advisory to Nordic energy transition to Asia-Pacific and African specialisms.

7. ERM (Environmental Resources Management)

Headquarters: London, UK | FY2024 revenue: ~US$1.3B (FY2023, latest disclosed) | Employees: ~8,000

ERM is the world’s largest pure-play environmental and sustainability consultancy. Owned by KKR since 2021, it sits at the boundary of management consulting and environmental advisory competing for board-level ESG mandates with the Big Four rather than with engineering firms.

Key capabilities:

• Environmental and social impact assessment, permitting, and stakeholder engagement.
• ESG, climate, and decarbonisation strategy and disclosure (TCFD, ISSB, CSRD).
• Technical and E&S due diligence for M&A and project finance.

Industries served:

• Energy, mining, manufacturing, technology, and chemicals.
• Financial institutions, private equity, and infrastructure investors.

What sets it apart: The only pure-play environmental and sustainability consultancy operating at this scale; Verdantix’s Green Quadrant continues to rate it as a leader in sustainability consulting alongside the Big Four.

Watch out for: Pure-play means no engineering or design-build for capex execution, ERM partners with firms like AECOM or Jacobs rather than replacing them.

Best for: Multinationals, PE sponsors, and infrastructure investors needing integrated E&S, ESG, and climate advisory across asset lifecycles.

8. Ramboll

Headquarters: Copenhagen, Denmark | FY2024 revenue: ~€2.0B | Employees: ~18,000

Ramboll is a Nordic engineering, design, and consultancy firm with strong environment & health, water, energy, and buildings practices. It is owned by the Ramboll Foundation, which means profits are reinvested rather than distributed a structural feature it leans into with clients on sustainability mandates.

Key capabilities:

• Environment & health consulting, including risk assessment, EHS, and remediation.
• Offshore wind, district energy, and energy-transition advisory.
• Climate-adaptation, nature-based solutions, and resilient infrastructure for cities.

Industries served:

• Energy and industrial clients across Europe and globally.
• Municipalities, regions, and international development programmes.

What sets it apart: Foundation ownership produces a distinctive culture and reinvestment posture, paired with arguably the strongest offshore wind and district-energy consulting practice in Europe directly aligned with the 2025–2030 European energy-transition pipeline.

Watch out for: Smaller scale than the top tier; on global megaprojects often plays specialist rather than prime contractor.

Best for: Clients valuing Nordic-rooted sustainability practice and deep expertise in offshore wind, district heating, and environment and health.

9. GHD

Headquarters: Sydney, Australia | FY2024 revenue: ~AUD 2.8B | Employees: ~12,000

GHD is a global professional-services company that started in Australia and has built a substantial Asia-Pacific, North American, and Middle East footprint over the past decade. It is employee-owned unusual among firms this size with a heritage in water and contamination work.

Key capabilities:

• Contamination, remediation, and PFAS investigation and treatment.
• Water and wastewater engineering and infrastructure resilience.
• Climate-resilience and infrastructure-sustainability support for public and private clients.

Industries served:

• Water and wastewater utilities, mining and resources, and energy.
• Transport and urban-development clients across Australia, North America, and the Middle East.

What sets it apart: Employee ownership at this scale is rare and produces noticeably lower turnover than the listed peers, particularly in senior technical roles a real advantage on multi-year programmes where staff continuity matters.

Watch out for: ESG strategy capability is narrower than ERM or Anthesis; better positioned as a technical environmental partner than a corporate sustainability advisor.

Best for: Utilities, mining, and infrastructure clients in Australia, New Zealand, Canada, and the Middle East seeking deep water and contamination expertise.

10. SLR Consulting

Headquarters: Maidenhead, UK | FY2024 revenue: ~£300M | Employees: ~3,300

SLR is an international environmental and sustainability consultancy serving energy, mining, infrastructure, built environment, and finance sectors. It has been owned by Ares Management since 2022 (having been previously owned by Charterhouse Capital Partners from 2018 to 2022) and continues to grow organically and through targeted acquisitions, particularly in North America and Asia-Pacific.

Key capabilities:

• Environmental impact assessment, permitting, and stakeholder engagement.
• Mining and minerals environmental work across exploration, operations, and closure.
• ESG advisory, climate-risk, and EHS compliance support.

Industries served:

• Mining, metals, oil and gas, and energy clients.
• Manufacturing, infrastructure, and financial sponsors.

What sets it apart: Mining and minerals environmental work is among the deepest in the industry from exploration through closure which is a structural advantage as critical-minerals projects (lithium, copper, rare earths) ramp up globally through 2026.

Watch out for: Outside extractives and energy, brand pull is weaker than peers; less of a natural prime for diversified infrastructure mandates.

Best for: Mining, critical-minerals, and energy clients needing senior-led E&S and permitting expertise with global coverage and boutique-style engagement.

11. RSK Group

Headquarters: Helsby, Cheshire, UK | FY2024 revenue: ~£1.0B+ | Employees: ~15,000

RSK is a multi-disciplinary environmental, engineering, and sustainability group that has executed roughly 200 acquisitions in five years to assemble one of Europe’s broadest environmental services platforms. Environment Analyst now ranks RSK among the top 10 global environmental consulting firms by revenue and one of the fastest climbers in the sector.

Key capabilities:

• Full lifecycle environmental consulting impact assessment, compliance, remediation, ecology.
• Site investigation, contaminated land, and geotechnical engineering.
• Health and safety management, asbestos, and water and waste-related services.

Industries served:

• Industrial, energy, and natural resources clients.
• Financial sponsors, public-sector clients, and infrastructure developers.

What sets it apart: The acquisition-platform model is genuinely distinctive at this scale RSK can deploy a one-stop integrated team across environmental, geotechnical, ecological, and engineering specialisms that competitors would have to subcontract.

Watch out for: Brand cohesion and quality consistency across so many acquired entities is an ongoing challenge; references should be checked at the specific business-unit level, not just at the group level.

Best for: UK, European, and Middle East clients wanting a broad, rapid-response integrated environmental and engineering supplier.

12. Anthesis Group

Headquarters: London, UK | FY2024 revenue: Not disclosed (est. ~£200M) | Employees: ~1,400

Anthesis is a purpose-driven sustainability consultancy that has grown rapidly through both organic growth and acquisition into a global climate and ESG player. The Carlyle Group announced its acquisition of a majority stake in June 2023 (valuing the firm at around £400M / US$508M), providing significant capital for further expansion. Anthesis is a Certified B Corporation.

Key capabilities:

• ESG and CSRD advisory, climate strategy, and sustainability integration.
• Proprietary digital tools including RiskHorizon (ESG screening), SCATTER (city GHG reporting), and Vastum (waste tracking).
• Carbon-removal project advisory and net-zero implementation support.

Industries served:

• Corporates across consumer, technology, financial services, and industrial sectors.
• Cities, investors, and supply-chain-led clients.

What sets it apart: Combination of strategy advisory and proprietary digital tooling most pure-play sustainability competitors license third-party platforms, whereas Anthesis builds its own plus Carlyle backing for continued acquisitions through 2026.

Watch out for: Heavy reliance on acquisitions for growth means integration overhead is real; quality and process consistency can vary between recently joined entities.

Best for: Corporates wanting a digital-forward sustainability and climate partner, particularly for CSRD readiness, supply-chain ESG, and net-zero programme delivery.

13. Royal HaskoningDHV

Headquarters: Amersfoort, Netherlands | FY2024 revenue: ~€480M | Employees: ~6,000

Royal HaskoningDHV is a Dutch independent engineering and project-management consultancy with strong maritime, water, and environmental practices. It has a long heritage in port and coastal engineering and applies that capability to climate-adaptation work in the Middle East, Africa, and Southeast Asia.

Key capabilities:

• Port, maritime, and coastal engineering with embedded environmental work.
• Water management, flood resilience, and water-sensitive urban design.
• Industrial environmental services and digital water solutions.

Industries served:

• Ports, shipping, and maritime infrastructure operators.
• Water utilities, municipalities, and industrial clients in MENA and Africa.

What sets it apart: Dutch maritime and water-engineering heritage applied to climate adaptation, port resilience, and water-sensitive urban design particularly active in markets where flood and coastal risk is intensifying fastest.

Watch out for: Mid-sized relative to AECOM or Arcadis; on megaprojects typically partners with larger primes rather than leading them.

Best for: Port, maritime, water, and climate-adaptation projects in the Netherlands, Middle East, Africa, and Southeast Asia.

14. Aurecon

Headquarters: Melbourne, Australia | FY2024 revenue: ~AUD 900M+ | Employees: ~7,500

Aurecon is an Australian engineering, design, and advisory firm with strong Southeast Asia hubs in Singapore, Indonesia, Vietnam, and the Philippines. It covers transport, water, energy, and environmental work, and is positioned more accessibly for ASEAN clients than the Anglo-American giants.

Key capabilities:

• Water, transport, and energy engineering with embedded environmental services.
• Climate-resilience and decarbonisation advisory for infrastructure clients.
• Digital engineering and asset-management tooling.

Industries served:

• Transport, water, and energy infrastructure clients in Australia, NZ, and ASEAN.
• Mining, defence, and government clients.

What sets it apart: Genuine regional depth across Southeast Asia from operational hubs in Singapore and Hanoi not just project teams flown in from Sydney which matters for clients in markets where local relationships and language capability drive delivery.

Watch out for: Smaller than GHD in Australia; brand recognition in North America and Europe is modest.

Best for: Asia-Pacific clients on water, transport, and environmental projects, particularly across Singapore, Indonesia, Vietnam, and the Philippines.

15. Nippon Koei

Headquarters: Tokyo, Japan | FY2024 revenue: ~JPY 130B (~US$870M) | Employees: ~6,000

Nippon Koei is Japan’s largest consulting engineer with a 75-year track record on water, environment, energy, and transport infrastructure. It is a primary delivery partner on JICA-funded and JBIC-financed development projects across Asia and Africa, and operates through a global network of regional offices.

Key capabilities:

• Water-resources, irrigation, and hydropower engineering and environmental management.
• Environmental impact assessment for ODA-funded transport, power, and urban projects.
• Disaster risk reduction and climate-resilience programmes in developing economies.

Industries served:

• Japanese ODA programmes (JICA, JBIC) across Asia, Africa, and Latin America.
• Asian governments, utilities, and infrastructure agencies.

What sets it apart: Positioned where no Western firm can compete inside Japanese-government-funded development corridors across Asia and Africa, where decades of relationships and local presence are very hard to replicate.

Watch out for: Outside ODA-funded work, brand recognition in Europe and the Americas is modest; English-language deliverables can require additional coordination on multinational teams.

Best for: Asian and African environmental, water, and infrastructure projects with Japanese government, JICA, or JBIC funding.

Tier 3: Specialist platforms and emerging firms

Specialist firms where targeted capability PFAS testing, US policy design, Latin American climate strategy can produce sharper expertise on the right mandate than a bigger competitor.

16. SRK Consulting

Headquarters: Johannesburg, South Africa (federated global) | FY2024 revenue: Not publicly disclosed | Employees: ~1,400 across 45+ offices

SRK is an independent, employee-owned consulting firm with a federated global structure across 45+ offices in Africa, the Americas, Europe, Asia, and Australia. It specialises in mining and earth-sciences environmental work and has arguably the deepest African mining-environmental footprint of any consultancy.

Key capabilities:

• Mining environmental and social impact assessment, tailings, and mine-closure planning.
• Acid rock drainage, water-balance modelling, and hydrogeology.
• Geotechnical engineering and earth-sciences advisory.

Industries served:

• Mining and metals operators and explorers across Africa, the Americas, and Australia.
• Mining-finance institutions and government regulators.

What sets it apart: Arguably the deepest acid rock drainage, tailings, and mine-closure expertise in the industry, combined with strong on-the-ground presence in African mining jurisdictions where most global firms run light teams.

Watch out for: Specialism on extractives and earth sciences means SRK is not a natural fit for non-mining environmental mandates such as ESG strategy or buildings.

Best for: Mining, metals, and earth-sciences clients with African or emerging-market exposure needing senior-led environmental, geotechnical, and social work.

17. Montrose Environmental Group

Headquarters: Little Rock, Arkansas, USA | FY2024 revenue: ~US$700M | Employees: ~3,400

Montrose is an NYSE-listed environmental services company offering testing, measurement, consulting, and remediation a vertically integrated model that lets a client move from contaminant detection to remediation without changing vendors. ENR consistently lists it in the Top 200 Environmental Firms.

Key capabilities:

• Environmental testing labs (including PFAS), fugitive-emissions monitoring, and air-quality measurement.
• Environmental consulting, site assessment, remediation, and reclamation.
• Digital services for environmental data management and reporting.

Industries served:

• Power, chemicals, oil and gas, real estate, and government.
• US federal, state, and local agencies.

What sets it apart: Vertically integrated testing-to-remediation model under one corporate roof is genuinely distinctive most competitors are either lab companies or consulting firms, not both and well-positioned to capture EPA’s post-2024 PFAS regulatory wave.

Watch out for: Heavy North American concentration; international footprint still building. The 2025 EPA enforcement pullback created near-term softness in some compliance-driven testing demand.

Best for: Industrial clients needing integrated testing, monitoring, and PFAS remediation, particularly in oil and gas, chemicals, and power generation.

18. Cadmus Group

Headquarters: Waltham, Massachusetts, USA | FY2024 revenue: Not disclosed | Employees: ~700

Cadmus is a technology-enabled strategic consultancy providing sustainability, energy, climate, water, and resilience services. It has been on ENR’s Top 200 Environmental Firms list for more than 20 years and specialises in policy design and programme evaluation work that pure-engineering firms generally don’t compete in.

Key capabilities:

• Policy design, programme management, and evaluation across energy efficiency, water, and climate.
• Utility programme design and demand-side management implementation.
• Strategy and market analysis for governments and utilities.

Industries served:

• US federal, state, and local agencies.
• Utilities, foundations, and international development donors.

What sets it apart: Deep policy, programme-design, and evaluation work for utilities and federal energy-efficiency programmes an analytical niche where pure-engineering firms rarely compete on equal terms.

Watch out for: Disproportionately exposed to US federal energy-efficiency and resilience programme funding, which has been reduced under the current administration; near-term backlog risk through 2026.

Best for: Public-sector and utility clients needing policy design, programme evaluation, and analytically rigorous climate and energy strategy work.

19. WayCarbon

Headquarters: Belo Horizonte, Brazil | FY2024 revenue: Not disclosed | Employees: ~250

WayCarbon is the leading independent climate and sustainability consultancy in Latin America. It is a Certified B Corporation with carbon-neutral operations, and develops three proprietary SaaS platforms (CLIMAS for climate-risk, MOVE for sustainability management, LICENTIA for environmental licensing) used in more than 40 countries.

Key capabilities:

• Climate policy, readiness, and implementation of climate-change projects for public and private clients.
• Climate-risk modelling and disclosure (TCFD, ISSB, CSRD) tailored to Latin American regulation.
• Emissions-offset programmes and forestry/conservation project advisory.

Industries served:

• Mining, steel, infrastructure, energy, oil and gas, forestry, pulp and paper.
• Financial institutions and multilateral organisations including UNDP, CAF, World Bank, IADB.

What sets it apart: The combination of climate consulting, proprietary digital platforms used in 40+ countries, and authentic Latin American regulatory grounding is unique no Anglo-American firm has the same depth in Portuguese- and Spanish-speaking markets.

Watch out for: Regional consulting focus (LATAM); software is global but the deepest client relationships are in Portuguese- and Spanish-speaking markets.

Best for: Companies with significant Latin America operations or supply-chain exposure, and global firms wanting digital climate-risk and environmental-licensing tooling.

How to choose the right environmental consulting firm

1. Engineering-heavy or strategy-heavy?

For design-and-build programmes and complex infrastructure, the global integrators AECOM, WSP, Jacobs, Tetra Tech, Stantec, Arcadis and the major regional firms (Ramboll, GHD, Royal HaskoningDHV, Aurecon, Nippon Koei) are the first port of call. For ESG strategy, CSRD readiness, and corporate transition advisory, pure-play firms (ERM, Anthesis) and policy specialists (Cadmus, WayCarbon) are more targeted.

2. Match geography and regulatory context

The biggest firms are North American and European in centre of gravity. For Latin American mandates, WayCarbon’s regulatory grounding is unmatched. For Japanese ODA-funded work across Asia and Africa, Nippon Koei is the natural prime. For ASEAN, Aurecon’s regional hubs matter. For African mining environmental work, SRK’s federated structure and on-the-ground depth are hard to beat.

3. Specialism: PFAS, climate, mining, digital

PFAS, hazardous waste, and remediation favour Tetra Tech, Jacobs, Montrose, AECOM, and GHD. Climate adaptation and resilience favour Arcadis, Royal HaskoningDHV, Ramboll, and WSP. ESG and CSRD strategy favours ERM, Anthesis, and the Big Four sustainability practices. Mining and critical minerals favour SRK and SLR. Digital and software-led sustainability favours Anthesis, WayCarbon, and Montrose.

4. Scale and engagement model

Large global firms bring capacity and breadth, but procurement and approval processes can be heavy. Mid-tier and specialist firms SLR, Anthesis, Cadmus, WayCarbon, Aurecon, SRK typically offer more senior-led teams and faster turnaround. Multi-year national or megainfrastructure programmes often benefit from a large integrator paired with a specialist climate, ESG, or digital partner.

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Frequently asked questions

What is an environmental consulting firm?

An environmental consulting firm advises public and private clients on managing the environmental impacts of their operations, projects, and supply chains. Services typically include environmental impact assessment, permitting, contamination remediation, water and air quality, biodiversity, ESG and sustainability strategy, climate-risk and adaptation, and regulatory compliance. The industry spans large integrated engineering firms, pure-play sustainability advisors, and specialist consultancies.

Who is the largest environmental consulting firm in 2026?

AECOM has held the #1 position on Engineering News-Record’s Top 200 Environmental Firms list for several consecutive years, with FY2024 revenue of approximately US$16.2 billion and around 51,000 employees. WSP Global is second by overall scale (CAD 16.2B revenue, ~73,000 employees), and Jacobs Solutions third (~US$11.5B revenue, ~45,000 employees) in the integrated environment-and-infrastructure category.

Which environmental consulting firm has the deepest PFAS practice?

Tetra Tech is widely regarded as having the world’s deepest dedicated PFAS practice, combining proprietary detection and treatment technology with extensive US federal and utility experience. Jacobs Solutions, AECOM, Montrose Environmental Group, and GHD also operate substantial PFAS teams. Demand surged after EPA’s April 2024 drinking-water standard for six PFAS compounds and the July 2024 CERCLA hazardous-substance designation for PFOA and PFOS.

What is the difference between a pure-play sustainability consultancy and an integrated environmental firm?

Pure-play sustainability firms (ERM, Anthesis, Cadmus, WayCarbon) focus on advisory work: ESG strategy, climate-risk, decarbonisation roadmaps, CSRD readiness, and management consulting. Integrated environmental firms (AECOM, WSP, Jacobs, Stantec, Arcadis) combine advisory with engineering, design, and project delivery for permitting, remediation, water, and infrastructure. Many clients pair an integrator for execution with a pure-play firm for board-level strategy.

How much do environmental consulting firms charge?

Fees vary widely by scope, geography, and firm tier. Day rates for senior consultants at major firms typically range from US$1,500 to US$4,000+, with junior staff at US$800–1,500. Environmental impact assessments and permitting are often quoted as fixed-fee projects ranging from US$50,000 to several million. ESG strategy and CSRD readiness retainers with pure-play firms commonly range US$200,000 to US$1M+ annually. Complex mining or large infrastructure mandates can run substantially higher.

How do the ENR Top 200, Environment Analyst, and Verdantix Green Quadrant rankings differ?

ENR Top 200 Environmental Firms ranks firms by environmental services revenue and is widely used as the benchmark for US infrastructure work. Environment Analyst tracks the global environmental and sustainability consulting market by revenue, growth, and market share. The Verdantix Green Quadrant evaluates sustainability and ESG consulting firms by capability and momentum on a 2x2 framework. The three emphasise different dimensions scale, growth, and qualitative capability respectively.

What does CSRD mean for buyers of environmental consulting services?

The EU’s Corporate Sustainability Reporting Directive originally required around 50,000 EU and non-EU companies operating in Europe to publish detailed sustainability disclosures. In February 2025 the European Commission proposed the Omnibus simplification package, which narrows scope to firms with 1,000+ employees and €450M+ turnover, and postpones second- and third-wave reporting by two years. Demand for disclosure advisory remains strong but is now concentrated in larger filers.

Bottom line for 2026

The environmental consulting market is consolidating at the top and proliferating in specialist niches at the same time. The integrators (AECOM, WSP, Jacobs, Tetra Tech, Stantec, Arcadis) will continue to win the large programmes, but the most interesting story for 2026 is the rise of mid-tier specialists ERM’s pure-play scale, Anthesis’s digital-plus-strategy combination, WayCarbon’s Latin American depth, SRK’s African mining footprint each of which can deliver sharper expertise on a focused mandate than the biggest firms can. For most buyers, the right answer is not one firm but a combination: an integrator for execution plus a specialist for strategy.

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