Florida’s stormwater regulations have undergone significant changes, impacting how we assess water quality and manage stormwater systems. It began with Senate Bill 7040, known as the Statewide Stormwater Rule Ratification Bill, which was signed into law on June 28, 2024.
The legislation establishes minimum stormwater treatment performance standards, requiring new development, including redevelopment over one acre, to reduce total phosphorus by 80% and total nitrogen by 55% to improve water quality. For project design, it mandates cost estimates for the annual operation and maintenance of stormwater management systems and establishes criteria for qualified stormwater inspectors.
The central component of the updated regulations is the concept of net improvement. According to Florida Administrative Code R. 62-330.301(2), net improvement refers to the enhancement of water quality through the implementation of onsite mitigation measures. These measures can include changes in land use or the implementation of stormwater Best Management Practices (BMPs). The goal is to demonstrate that the proposed activity will result in a net improvement of the nutrient parameters regulated by the state, specifically Total Nitrogen (TN), Total Phosphorus (TP), and Total Suspended Solids (TSS).
In practice, net improvement can be achieved through enhanced BMPs such as increased retention volume, nutrient-reducing media, biofiltration systems, or other onsite measures that provide additional pollutant removal capacity. Tools such as BMPTrains, or equivalent modeling or manual calculations, may be used to support net improvement evaluations.
Before the 2024 rule change, only projects discharging directly or indirectly to impaired water bodies were required to demonstrate net improvement for TN and TP. Following the ratification of Senate Bill 7040, this requirement now applies to all sites, regardless of the impairment status of the receiving water body, and includes TSS as an additional parameter. Net improvement must be demonstrated using the more protective of the two approaches: a pre- versus post-development runoff analysis for TN, TP, and TSS, or a nutrient reduction efficiency method that specifies required reduction percentages for each parameter.
The Statewide Stormwater Rule also introduced more rigorous operation and maintenance requirements for stormwater management systems. Entities responsible for these systems must now submit a cost estimate for perpetual operation and maintenance, along with a financial capability certification, as part of the Environmental Resource Permit (ERP) application package. In addition, the updated rule mandates the development of a comprehensive operations and maintenance plan that outlines procedures to ensure long-term system functionality and continued compliance with water quality standards. These requirements ensure that stormwater systems remain functional throughout their lifespans, rather than meeting performance targets only at construction.
The new rule also requires that stormwater management system inspections be conducted, certified, and submitted by a qualified inspector. To meet this requirement, the inspector must either be a registered professional, work under the supervision of one with proper documentation, or have completed training within the past five years that covered key topics such as reading construction plans, understanding traditional and non-traditional BMPs, identifying system failures, and performing inspections in compliance with applicable regulatory standards. As part of the certification process, the qualified inspector must also submit a Stormwater Facility Inspection Checklist.
The stormwater rules do not apply retroactively to existing site developments with valid, unexpired conceptual, general, or Individual ERPs issued before the effective date of June 28, 2024. Existing developments are not required to retrofit their stormwater management systems unless a major modification is proposed. Minor modifications remain subject to the original permitting rules, provided they do not result in significant impacts on water resources. To qualify for this grandfathering provision, applicants must demonstrate that the proposed changes will not affect treatment, attenuation, or discharge functions; increase off-site discharge or environmental impacts; or reduce retention/detention capacity, flood-control elevations, or pollution-removal efficiency. Additional grandfathering provisions for public transportation projects, projects submitted to local government agencies, projects involving ecosystem management agreements, and Developments of Regional Impact, defined as developments that substantially affect the health, safety, or welfare of citizens in multiple counties, are outlined in Section 3.1.2 of the ERP Applicant’s Handbook, Volume I, effective June 28, 2024.
The new net improvement requirements established by the Statewide Stormwater Rule took effect on June 28, 2024, making the implementation date December 28, 2025. ERP applications that are deemed complete before this deadline are exempt from these updated standards. In contrast, other components of the rule took effect immediately on June 28, 2024, including the requirements for operation and maintenance plans, long-term cost estimates, and system inspections. The qualified inspector provisions, which outline specific credentials and training standards for inspectors, became effective one year later, on June 28, 2025.
Understanding these requirements early in project planning is critical, as incorporating net improvement strategies and O&M obligations upfront can prevent costly redesigns later in the permitting process. By staying informed and adapting to the new regulations, we can ensure that our projects do not adversely impact Florida’s water quality or environmental health.
About the Authors:
Mike Radford, P.E., is a licensed Professional Engineer with nearly two decades of experience specializing in landfill and solid waste design, stormwater management, and construction oversight. He has served as Project Manager and Engineer of Record for numerous landfill projects, including cell design, expansions, closures, and methane gas management systems.
Sara Perez Lopez, Staff Professional, provides engineering support for landfill design, permitting, and reporting in the southeastern U.S. Sara’s experience includes preparing Environmental Resource Permit applications for landfill expansions and renewable natural gas facilities, conducting NPDES inspections, and performing Title V visible emissions testing for landfill gas flares. Her experience includes working with the Florida Department of Environmental Protection and the Southwest Florida Water Management District, regulating wetland dredging, filling, and stormwater runoff activities.
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