Does your Massachusetts property require permitting?
EPA’s Residual Designation in Charles River, Mystic River, and Neponset River Watersheds: Key Implications for Private Properties
Authored by: Alexandra (Allie) Bailey, PE
On October 31, 2024, the United States Environmental Protection Agency (USEPA) released a Draft General Permit for Private Commercial, Industrial, and Institutional (CII) Stormwater Discharges in the Charles, Mystic, and Neponset River Watersheds in Massachusetts (Draft CII Permit). The Draft CII Permit proposes to regulate stormwater discharges (stormwater runoff, snow melt runoff, and surface runoff and drainage) from certain privately owned Massachusetts commercial, industrial, and institutional properties that discharge to private separate storm sewer systems, municipal separate storm sewer systems (MS4s), or directly to waterbodies within the Charles, Mystic, or Neponset watersheds.
The USEPA has determined that stormwater discharges from these sites contribute to violations of Water Quality Standards, specifically phosphorous, and have designated these discharges for National Pollutant Discharge Elimination System (NPDES) permitting.
Who is affected?
As currently proposed, the Draft CII Permit would impact privately owned commercial, industrial, and institutional properties with one or more acres of impervious cover (e.g., rooftops, parking lots, driveways) in the Charles, Mystic, and Neponset watersheds. This also includes mixed-use parcels with some level of commercial land use associated with them (for example, multi-family property with first floor retail). The USEPA has also indicated that while straight multi-family residential parcels are not currently included in the draft permit designation, they may be included in future designations.
Using tax parcels and geospatial mapping, the USEPA created an interactive mapping tool to help property owners identify if their property requires permitting.
What is required?
Once permitted, each property must calculate their site-specific reduction in phosphorus loading based on the quantity of impervious cover and the target phosphorous removal for the watershed, then create a plan to meet that reduction in specified time periods. Methods for reduction include:
- Implementation of structural (design and construction of infiltration trenches, porous pavements, infiltration basins, etc.) controls and/or non-structural controls (street and parking lot sweeping, catch basin cleaning, leaf litter collection program);
- Funding off-site reductions through local watershed group; or
- Trading off-site reductions with another permitted site.
The regulatory structure for off-site reductions has not yet been outlined in the draft permit.
When will this take effect?
Comments on the Draft CII Permit are due to the USEPA on March 17, 2025. Comments on the draft permit should be submitted via email to R1.RDA@epa.gov, and should include “Comments on the Preliminary Designation and/or Draft CII GP” in the subject line. Alternatively, comments may be provided to NAIOP’s Government Affairs committee (Anastasia Daou, daou@naiopma.org) for consideration in their comment letter.
After the USEPA prepares written responses to comments, they are anticipated to issue the final permit; then, parties that submitted comments during the public comment period have the ability to appeal the final CII Permit in federal court.
While the exact date the permit will be finalized is not known, Roux advises that all property owners and developers should begin to proactively consider the impacts this permit may have on their properties.
What can Roux do to help?
Roux’s team of engineers and environmental professionals can assess and interpret how the Draft CII Permit may impact your property, evaluate potential long-term costs, and advise on regulatory timeframes. Roux has extensive experience guiding our clients through new permitting regulations in Massachusetts and beyond. While navigating these regulatory changes, Roux can assist with designing an approach tailored to site-specific objectives and goals. Please contact our team with any questions or concerns below.
