PFAS-credentialed compliance consultants that serve California. Listings include both firms headquartered in California and out-of-state firms with active California project coverage. See the California compliance page for contamination data and regulatory deadlines that drive this work.
Employee-owned environmental engineering firm specializing in water and wastewater. PFAS treatability studies and full-scale design for U.S. utilities.
Major federal contractor for DOD AFFF-impact investigation, IRP/MMRP site work, and PFAS remediation under USACE and AFCEC IDIQs.
Specialist water-treatment consultancy with deep PFAS bench- and pilot-study experience for California utilities. Founders include former MWDSC water-quality leadership.
Largest U.S. firm exclusively dedicated to water/wastewater engineering. Significant PFAS pilot and design work for California and Western U.S. utilities.
West Coast water-focused engineering firm. PFAS treatment design and pilot work for California and Pacific Northwest municipalities.
Top-5 global engineering firm with deep PFAS practice — treatment system design-build, AFFF investigation at DOD installations, and regulatory consulting.
Global consultancy with one of the most-cited PFAS practices in industry. AFFF impact investigation, foam fractionation R&D, and litigation-support technical work.
Employee-owned engineering firm with a substantial municipal water practice. PFAS treatment design, pilot studies, and SRF-funded project delivery.
Privately-held engineering firm with a deep municipal water practice. PFAS treatment evaluations, GAC and IX pilot studies, EC-SDC grant application support.
Water-utility-focused PFAS and treatment specialty consultancy. UCMR sampling, treatment evaluation, source water assessments, and SDWA compliance planning.
PFAS-treatment-specialty consultancy founded by ex-Hazen and Sawyer PFAS leaders. UCMR support, treatment evaluation, and regulatory compliance planning for water utilities nationwide.
Environmental engineering and applied science firm widely recognized as a PFAS R&D thought leader. Leading work on in-situ treatment, colloidal activated carbon, and AFFF site characterization.
Water-focused engineering firm known nationally for PFAS treatment research and design. Led pilot work on GAC, IX, and RO for major utilities including OCWD and NYC DEP.
Global testing, inspection, and certification firm. PFAS analytical services across drinking water, wastewater, soil, and food packaging matrices.
Employee-owned environmental consulting and engineering firm. PFAS UCMR sampling support, AFFF site investigation, and compliance planning for water systems and DOD clients.
Sustainability and environmental consultancy with a global PFAS service line — site investigation, product-stewardship advisory, and CERCLA/regulatory positioning support.
Global engineering firm with significant U.S. PFAS investigation and remediation work, including AFFF impact assessments and industrial-site liability evaluations.
Global engineering and EPC firm with PFAS treatment design, site investigation, and regulatory advisory work across federal and municipal sectors.
Environment & Health practice with a long PFAS toxicology and site-investigation track record, including expert-witness work in major PFAS litigation.
Multi-discipline engineering firm with combined municipal water treatment and remediation practices. Active in PFAS pilot studies, design-build, and Brownfields assessment.
WSP acquired Wood's E&IS practice in 2022. Global PFAS investigation, AFFF site work, and treatment evaluation capabilities across federal and private-sector clients.