Managing stormwater effectively is one of the most critical—and legally required—elements of operating a large construction site in the United States. With an increase in extreme weather, stormwater management has become a top priority for construction contractors nationwide.
This article outlines current regulations, best practices and actionable steps contractors can take to reduce risk, improve project performance and stay compliant.
UNDERSTANDING THE REGULATORY LANDSCAPE
The U.S. Environmental Protection Agency (EPA) regulates stormwater discharges from construction activities through the National Pollutant Discharge Elimination System (NPDES). Sites that disturb one acre or more must obtain permit coverage under the Construction General Permit (CGP) or a state-equivalent permit in delegated states.
Many states operate their own NPDES programs with additional local regulations, so contractors must understand both federal and state-specific requirements. It’s important to note that while the EPA’s CGP is in effect in certain jurisdictions, many states have their own NPDES permitting programs with state-specific requirements. For example, the Florida Department of Environmental Protection (FDEP) administers its own Construction Generic Permit (CGP) for stormwater discharges from construction activities within Florida. Contractors should always check state guidelines and requirements for compliance.
ACTIONABLE STEPS CONTRACTORS CAN TAKE
Whether you’re managing a new site or improving an existing process, here are steps contractors should implement for effective stormwater management:
1. Create a Site-Specific SWPPP
Your Stormwater Pollution Prevention Plan (SWPPP) is the foundation of compliance. It must include:
- Site maps with drainage patterns and pollutant sources.
- Descriptions of all BMPs used on-site.
- Inspection schedules, corrective actions and training protocols.
2. Use Tiered BMPs for Erosion and Sediment Control
Implement a combination of structural and non-structural Best Management Practices (BMPs) such as:
- Silt fences and wattles to trap sediment near the perimeter.
- Construction entrances with aggregate pads to prevent track-out.
- Sediment basins or traps for runoff retention on large sites.
- Mulching, hydroseeding or erosion control blankets on exposed soils.
3. Plan for Storm Events
Have a rain-response protocol that includes:
- Staging equipment and materials to higher ground.
- Checking BMPs before and after heavy rainfall.
- Using smart sensors to monitor water levels in basins or drains.
- Have a disaster readiness plan in place.
4. Train Crews on Stormwater Awareness
Every team member should understand:
- How to identify BMP failures.
- Proper materials handling to reduce pollutants.
- What to do during storm inspections.
A LOOK AT THE NUMBERS
Recent findings highlight the importance of stormwater management strategies:
- The EPA estimates construction sites contribute 20–150 tons of soil loss per acre per year without BMPs.
- Non-compliance fines under the Clean Water Act can reach up to $64,618 per day per violation.
SEVERE WEATHER AND STORMWATER MANAGEMENT
Severe storms can cause major project delays and damages, reinforcing the need for resilient site planning.
In 2024, the United States experienced a notably active hurricane season, with several storms significantly impacting construction sites and their stormwater management systems. Hurricanes such as Beryl, Helene and Milton brought intense rainfall and flooding, challenging existing infrastructure and highlighting vulnerabilities in construction site preparedness.
The heavy rainfall and storm surges associated with these hurricanes overwhelmed stormwater controls at numerous construction sites. In Florida, for example, back-to-back hurricanes resulted in massive sand deposits, with some areas experiencing accumulations up to 5 feet deep. This not only disrupted construction activities but also complicated stormwater runoff management, as the excessive sand altered drainage patterns and clogged existing systems.
In North Carolina, Hurricane Helene led to unprecedented flooding, with Asheville experiencing what was described as a 1,200-year flood event. Construction sites in the area faced significant challenges as stormwater systems were unable to cope with the volume of water, leading to site inundation and sediment displacement as roads, bridges and electrical systems were all washed away by floodwaters.
LOOKING AHEAD
National Level: As of March 2025, several developments have emerged in stormwater management regulations and practices that are pertinent to construction contractors in the United States. Notably, the U.S. Environmental Protection Agency (EPA) has proposed updates to the Multi-Sector General Permit (MSGP) for industrial and construction activities. The comment period for these proposed changes was extended to April 4, 2025.
State Level: Several states have stormwater general permits set to expire or be renewed in 2025, including Alaska, Minnesota, Mississippi, North Dakota, Tennessee, Vermont and Wisconsin. Contractors operating in these states should anticipate potential changes to state-specific stormwater regulations and prepare to adapt their Stormwater Pollution Prevention Plans (SWPPPs) accordingly.
Local Level: Cities like Portland, Oregon, have implemented new Stormwater Management Manuals effective March 1, 2025. These manuals set forth city policies and design requirements for stormwater management on development and redevelopment projects. Contractors working in such jurisdictions should familiarize themselves with these updated local requirements to ensure compliance.
Staying informed about evolving regulations and incorporating updated BMPs into construction practices is essential for contractors to maintain compliance and effectively manage stormwater on large construction sites. Stormwater can either be a setback—or a strategic advantage.
Photo credit: CHICAGOPHOTOGRAPHER/BIGSTOCKPHOTO.COM
