NYSDEC’s Part 375 amendments: Over 6 months in, what real estate professionals should know - by Kevin Taylor
The year 2026 has brought major changes to New York State’s environmental regulations. Effective December 31, 2025, the New York State Department of Environmental Conservation (NYSDEC) updated Title 6, Part 375 of the New York Codes, Rules, and Regulations (6 NYCRR Part 375). These rule changes are currently reshaping environmental remediation in areas such as development planning, deal structuring, environmental due diligence, and long-term asset management.
What are the changes to 6 NYCRR Part 375?
Broadly speaking, the amendments to 6 NYCRR Part 375 change how contaminated sites are investigated, remediated, and approved.
Qualified Environmental Professionals (QEP), licensed professionals who oversee remediation work, are now subject to additional certification requirements. This includes attestation that all environmental data submitted is complete and accurate and that the remediation work followed approved plans. Where deviations do occur in the field, they must be documented and justified in real time. QEPs must also attest that any information used to request a Certificate of Completion (COC), a document confirming that a site has been cleaned up to regulatory standards, is accurate and defensible. These updates better align 6 NYCRR Part 375 with the 2015 and 2022 statutory amendments to the New York State Brownfield Cleanup Programs.
The standards for obtaining and maintaining a COC have also increased, requiring stronger evidence to indicate the cleanup goals have been met and more rigorous documentation for ongoing engineering controls (physical measures to reduce contaminant exposure, such as composite cover systems) and institutional controls (administrative measures such as land-use restrictions). The amendments also provide clarity on when a COC can be changed later, should site conditions or cleanup objectives change.
Across all remedial phases, the new, enhanced documentation requirements include more robust data analysis, clearer visualization tools such as maps and tables, more detailed explanations of remediation strategies used, and more transparent documentation of soil removal, waste handling, and other on-site activities. Daily field reports featuring progress summaries, site maps, air monitoring data, and more, must be submitted to NYSDEC on a daily basis.
QEPs and environmental consultants are not the only ones that must contend with stricter regulations, either; expanded administrative and recordkeeping rules require developers, consultants, and property owners alike to maintain complete project files, detailed field work records justifying on-site project decisions, and documentation of long-term monitoring and maintenance obligations.
What does this mean for real estate?
Developers, lenders, investors, and any other major real estate stakeholders will have to be more cautious at every stage of the project; for stakeholders to protect themselves from liability, environmental review must be more stringent, legal review more thorough, progress updates more frequent, and the financing process more scrutinous.
For developers and consultants, these changes can directly impact project feasibility. The increased fieldwork and frequent reporting requirements may require a large on-site presence and more regular communication between stakeholders, so it is imperative that developers take these factors into account when constructing project timelines, developing budgets, and selecting consultants and/or contractors. Additionally, because 6 NYCRR 375 is now more closely aligned with current brownfield rules, there may be a greater interest in rehabilitating brownfield properties rather than building on undeveloped land.
Lenders, investors, and other financiers will likely require more regular progress updates. The greater financial risk posed to these institutions also mean that they will be more likely to rely on third-party verification and may not even disburse funding without documented evidence of Part 375 requirements having been met.
What’s next?
One of the best ways a project owner can prepare for these challenges is by consulting with a multidisciplinary firm early on in the process. A firm with on-staff QEPs is essential, as is the presence of a licensed Professional Engineer, who will need to sign off on any certification documents submitted to the NYSDEC. A multidisciplinary firm can also help guide the project through most or all of its phases, from pre-environmental design to post-environmental construction and engineering, streamlining communication and reducing the need for additional subconsultants. Furthermore, a firm with significant brownfield experience is likely to have already encountered and navigated many of the 6 NYCRR Part 375 regulations, as these rules have been in New York’s brownfield regulations far longer.
These amendments are designed to strengthen transparency while providing a consistent set of rules for builders to follow. Though these rules can impact budgets and timelines, incorporating the right consultant early enough in the project process can make the project progress more smoothly and with greater levels of trust, consistency, and accountability.
Kevin Taylor, P.E., P.G., CIH| vice president & environmental discipline director at H2M architects + engineers, Melville, NY.