On October 31, 2024, Region 1 of the United States Environmental Protection Agency (“EPA”), which covers the New England states, proposed sweeping new requirements to regulate stormwater discharges from certain commercial, industrial, and institutional (“CII”) properties into three watersheds in Eastern Massachusetts. The proposal comprises two related actions: (1) a preliminary residual designation determination (“Determination”) pursuant to EPA’s authority under the Federal Clean Water Act requiring a permit for certain stormwater discharges in the Charles, Mystic, and Neponset River watersheds, affecting more than 1,500 parcels of land in over 50 municipalities, and (2) a draft of a general permit authorizing and setting requirements for the discharge of stormwater into the three watersheds (the “CII General Permit”). Publication of the drafts triggered a 90-day public comment period on both the Determination and the draft CII General Permit.
The Clean Water Act grants EPA so-called residual designation authority (“RDA”) to require National Pollutant Discharge Elimination System (“NPDES”) permits for stormwater discharges when it determines that the discharge contributes to a violation of a water quality standard or is a significant contributor of pollutants to the waters of the United States or that such action is needed to protect water quality. Once it becomes final, the Determination, which was originally published in September 2022, will require all private commercial (including mixed use), industrial, and institutional properties with one or more acres of impervious cover in any of the three watersheds to obtain an NPDES permit. The Determination and related permitting are intended to reduce pollution from nutrients and pathogens that run off impervious surfaces in stormwater and enter the rivers. EPA is specifically targeting phosphorus, which it considers an “indicator pollutant” that can be regulated as a means to target a group of pollutants. Thus, controlling phosphorus is expected also to limit nitrogen as well as reduce bacteria and other pathogens.
The permit requirement applies to both existing sites and sites that subsequently are developed to exceed the impervious cover threshold, and it applies whether the discharge occurs through a private separate storm sewer system, through a municipal separate storm sewer system (“MS4”), or directly into the any of the three rivers or their tributaries. It does not affect discharges to combined sanitary/stormwater sewer systems with a permitted publicly owned treatment works (“POTW”). The Determination only affects privately owned properties; accordingly, it does not apply to any property that is subject to the Massachusetts MS4 stormwater general permit. It also is inapplicable to properties that have an individual NPDES stormwater permit. Dischargers operating under EPA’s multi-sector general permit however, are subject to the CII requirements for portions of their sites not covered by the multi-sector permit. Although, as written, the draft does not apply to residential sites, EPA is requesting comment on whether multifamily properties, including privately owned housing with five or more units, should also be required to obtain a permit.
Overview of CII General Permit
General permits are designed to cover multiple dischargers who have similar operations and types of discharges. They have standardized conditions and therefore by-pass the site-specific evaluations necessary for an individual permit. As a result, general permits are quicker to obtain. To avoid the need for many hundreds of individual CII permits, EPA has proposed the CII General Permit which is available to all dischargers who meet its requirements.
The CII General Permit identifies eligible dischargers, states who may be the permittee, establishes the process to obtain coverage, mandates a specific phosphorus reduction target along with requirements and a schedule for meeting the target, and contains various reporting and recordkeeping obligations. The general permit is available for CII sites with at least one acre of impervious cover. Impervious surface includes anything that significantly impedes infiltration of water into underlying soil, such as roads, driveways, parking areas, buildings, rooftops, artificial turf, and compacted gravel or soil. Under the general permit, impervious cover is measured by combining contiguous parcels of land that are owned by the same entity even if they are separated by a roadway, garden, or similar feature that interrupts the continuous flow or use of the land or by an easement, as long as the land on either side is owned by the same entity. EPA is seeking comment on this approach.
The owner of the site (or contiguous sites) is considered the permittee, unless a written agreement gives another entity the authority to make decisions regarding operational control of one or more sites, in which case the operator is the permittee. Where a property has multiple lessees, however, the draft permit designates the owner as the permittee regardless of whether an agreement provides otherwise. EPA is seeking comments on this approach. In particular, EPA asks the public to weigh in on how a shopping center with a single owner, but multiple tenants, should be treated for permitting.
Notice of Intent
To obtain coverage under the permit, the owner or operator of an existing site must file a notice of intent (“NOI”) and receive authorization from EPA to discharge. An owner of multiple contiguous sites needs to secure coverage under a single NOI applicable to all of the sites. EPA is requesting comment on how to handle situations where a landowner has multiple noncontiguous properties. One suggested alternative is for the permittee to submit a single NOI and receive authorization from EPA for all noncontiguous properties that it owns or operates. In that case, phosphorus reductions could be done on any of the sites covered by the authorization. Alternatively, a separate NOI and authorization could be required for each noncontiguous site owned or operated by the same entity.
For existing sites, NOI filing deadlines are phased in to avoid overburdening applicants and to allow EPA time to address them in a controlled fashion. Properties with five or more acres of impervious cover must submit the NOI no later than six months after the effective date of the CII General Permit. Properties with greater than or equal to two but less than five acres of impervious cover have up to 12 months after the effective date of the permit to apply, and properties with one or more acres but less than two have 24 months. For new or increased impervious cover, an NOI is required at least 30 days before occupancy of the site or termination of any construction stormwater general permit, whichever occurs first. This requirement applies to newly developed sites; sites that had less than one acre of impervious cover prior to an increase above the acreage threshold; and sites not yet permitted that increase impervious cover to exceed the next impervious cover acreage category (i.e., 2 or 5 acres). Additional NOIs must be submitted when the amount of impervious cover changes and for the implementation of stormwater controls.
Where site ownership or identity of the operator changes, the new permittee has 30 days after the property transfer or change in operator to submit an NOI. In addition, the former permittee must file a notice of termination within 30 days after permit coverage becomes active for the new owner or operator. All permit requirements, including reporting obligations, continue until EPA approves the notice of termination. When a property is sold, the seller must confirm that all installed structural stormwater control measures are maintained and functioning as designed and certify to the same in the notice of termination.
EPA’s timeframe for acting on NOIs will vary depending on the amount of impervious cover. The agency plans to issue determinations of authorization for existing large sites (five or more acres of impervious cover) within six months following the deadline to submit an NOI. For medium-sized (two or more acres but less than five) and small sites (one or more acres but less than two), EPA will issue its determination within 12 months following the NOI deadline. For new or increased discharges, EPA will issue the authorization within six months following the deadline for NOI submittal. The effective date of permit coverage will be as indicated on the authorization. In the absence of EPA’s written notification of permit coverage, the owner or operator is not authorized to discharge under the permit.
Phosphorus Control Requirements and Compliance Schedule
The CII General Permit establishes a multiyear compliance schedule to reduce the amount of phosphorus and other pollutants discharged in stormwater. Ultimately, all permittees must reduce phosphorus in stormwater from their sites by 65% in the Charles River watershed, 62% in the Mystic River watershed, and 60% in the Neponset River watershed. To achieve the reduction, the permit imposes various requirements and interim steps. Within two years from authorization to discharge, permittees must develop a stormwater pollution control plan (“SPCP”), which sets their site-specific phosphorus reduction responsibility. Within six years of authorization, permittees of existing sites must meet an interim limit of 50% of the site-specific phosphorus reduction requirement and within 11 years must reach 100% of that requirement. Owners of newly developed sites, however, will not benefit from the extended compliance schedule. Instead, they must meet the phosphorous reduction requirements within two years of permit authorization in addition to having the SPCP in place. EPA is requesting comments on the appropriateness of the compliance schedule.
The specific pollutant load reduction responsibility for existing sites is determined by taking the average annual phosphorus load of the site’s total existing impervious cover at the time of the permit’s effective date and applying the applicable pollutant reduction percentage for the watershed. A technical appendix to the permit explains how to make the calculation. Sites newly developed after the permit becomes effective may not add phosphorus load from runoff generated by the new impervious cover. Special rules apply for redevelopment sites. These are locations that add impervious cover after the effective date of the permit to a site that already meets the threshold. No net increase in phosphorus load may be added by runoff from the new impervious cover. Accordingly, the phosphorus runoff load from the new impervious cover may not exceed the load that existed for the previous pervious area. Existing impervious portions of the site that is being redeveloped must comply with the pollution reduction requirements for existing sites. Redevelopment projects that do not change the total net area of impervious cover must meet the pollution requirements for existing sites.
The SPCP provides the road map for reducing phosphorous. The plan must calculate site-specific pollutant load reductions based on the amount of impervious cover and state how the permittee will meet the 50% six-year interim limit and 100% reduction target using structural and/or nonstructural stormwater controls.
Stormwater Control Measures
Permittees may choose from a variety of structural and nonstructural stormwater control measures. Upon implementation of any stormwater control measure, the permittee must notify EPA and identify the measure being used. The SPCP must specify the pollution reduction achieved by each control calculated by using methods set out in the permit. Stormwater management system design needs to be at least as stringent as the 2008 (or updated) Massachusetts stormwater handbook. Long-term operation and maintenance activities are required and must be documented. Where permittees already have structural stormwater control measures in place, they can receive credit towards their phosphorus reduction target, provided that they have records to support the reduction and certify annually that the control measures are being maintained.
Nonstructural control measures include sweeping of streets and parking lots, leaf litter collection, and cleaning of catch basins, all of which are intended to keep pollutants from entering the rivers. Pollutant removal percentages allocated to each control measure are set forth in a technical appendix to the permit and the permittee must maintain records of sweeping and cleaning, along with associated pollution reduction credit calculations.
Permittees will have three options to reduce phosphorus: First, they may use on-site structural or nonstructural stormwater control measures within the watershed. Second, they may use off-site stormwater control measures implemented at another eligible CII or MS4 location within the watershed that is not the permitted site. This may involve funding for a regional phosphorus control project undertaken by a local watershed management group or co-funding of a stormwater management project with another permittee. Where a regional approach is used, the permittee must enter a legally binding agreement with the local watershed management group. The agreement must be limited to the boundary of the watersheds where the permittee’s site is located. Co-funding also must be done through legally binding agreements and relate to the relevant watershed. Third, a permittee may engage in trading of phosphorus reduction credits with another permitted site in the same watershed. Thus, if a permitted site reduces its phosphorus by more than the required percentage, it may sell “credits” for the excess reduction to another discharger.
Permittees who use an off-site option remain responsible for ensuring compliance with the permit. Off-site reduction approaches must include operation and maintenance plans identifying the party responsible and actions necessary to ensure the stormwater control functions properly. The party receiving the removal credits must certify annually that the O&M activities are occurring.
Best Management Practices
The CII General Permit requires the use of best management practices (“BMP”) consisting of an on-site chemical application management plan (“OCAMP”) and stormwater training. The OCAMP, which is prepared in connection with the SPCP, deals with landscaping and lawn maintenance and includes a separate winter maintenance plan. Lawn maintenance practices must address erosion or poor vegetative cover, management of trash containers, and compliance (within 24 months of authorization) with Massachusetts regulations relating to plant nutrient application requirements for agricultural land and non-agricultural turf and lawns. The OCAMP is due within two years of the date of authorization to discharge. Annual certification must be made that all requirements of the chemical application management plan are being implemented.
With respect to winter maintenance, EPA acknowledges that public safety often requires de-icing with salt. Accordingly, instead of prohibiting salt, the permit calls for reducing the amount of chloride used through calibration, low-salt zones, and application rate standards. Permittees must track and report the total amount of salt used each season and the application rate in pounds per acre. Winter maintenance plans must outline winter operations at the site, describe calibration of equipment, identify mechanical snow removal practices, discuss the storage, use and monitoring of salt, and analyze other potential de-icing materials.
The training requirement calls for persons responsible for implementing the permit to attend two annual trainings in stormwater management and related topics starting two years after authorization under the permit.
Records and Annual Reports
The permit includes a variety of record-keeping requirements. Records must be retained for at least three years after the date coverage under the permit expires or is terminated.
Permittees must submit annual reports summarizing activities of the prior year. The first report is due 14 months after permit authorization. Besides information on pollution reduction activities undertaken during the prior year, the annual reports must certify as to various required steps under the permit including that:
- a storm sewer system map has been completed within 12 months of the effective date of authorization and remains accurate;
- operating and maintenance is occurring at each structural stormwater control measure along with the date of last maintenance;
- nonstructural controls continue to be implemented;
- an SPCP has been developed and is up to date;
- the OCAMP has been developed and is being implemented along with the total amount of salt used per acre each season and the application rate in pounds per acre.
At the end of the sixth and 11th year, the annual report must certify to compliance with, respectively, the 50% and 100% pollution load reduction requirements.
EPA has scheduled public meetings and public hearings to be held in January on the Determination and CII General Permit. Written comments are due by January 29, 2025.
