Stormwater Discharges from Municipal Sources-Developing an MS4 Program
Owners/operators of regulated municipal separate storm sewer systems (MS4s) are required to develop, implement, and enforce a stormwater management program (SWMP). The focus of the SWMP is to describe how the MS4 will reduce the discharge of pollutants from its sewer system and addresses these program areas:
- Construction Site Runoff Control
- Illicit Discharge Detection and Elimination
- Pollution Prevention/Good Housekeeping
- Post-Construction Runoff Control
- Public Education and Outreach
- Public Involvement/Participation
- Program Effectiveness
- Total Maximum Daily Loads
Use the guidance and references on this page to help you develop your SWMP.
Include a program in your SWMP to reduce pollutants in stormwater runoff to your MS4 from construction activities that disturb ≥ 1 acre of land.
- Construction Fact Sheets
- The Menu of BMPs for Construction Site Runoff Control —Describes best management practices (BMPs) for MS4s and construction site operators to address stormwater runoff from active construction sites.
- Developing Your Stormwater Pollution Prevention Plan: A Guide for Construction Sites —Provides guidance for construction site operators, including SWPPP templates and a sample inspection form.
Stormwater and certain authorized types of uncontaminated non-stormwater are the only discharges that should enter your MS4. Illegal dumping and connections can result in illicit discharges of non-stormwater wastes like car oil and sanitary waste into it. Include a program in your SWMP to detect and eliminate illicit discharges to your system.
- Illicit Discharge Detection and Elimination —Describes BMPs for identifying and eliminating illicit discharges and spills to storm drain systems.
- IDDE Fact Sheets
- IDDE Guidance Manual —Outlines practical, effective IDDE techniques for MS4s. Electronic resources associated with the manual:
- Outfall Reconnaissance Inventory (ORI) Form (doc)
- ORI Database - Use to record and manage ORI data (Note: You must download the file to edit it)
- Hotspot Site Investigation Form
- Chemical Mass Balance Model (CMBM) Setup - Executable file for sophisticated technique used to differentiate among flow types at outfalls with blended flows
- CMBM Sample Input File (xls) - CMBM Sample Input File
- Hotline Tracking Form (doc)
- IDDE Supporting Materials – Provides methods for detecting illicit discharges, identifying sources, quantifying discharges, and examples of what communities are doing to fix problems.
- Methods for Detection of Inappropriate Discharges to Storm Drainage Systems: Background Literature and Summary of Findings
- Source Verification of Inappropriate Discharges to Storm Drainage Systems
- Quantification of Escherichia Coli and Enterococci levels in Wet Weather and Dry Weather Flows
- Inappropriate Discharge Detection and Elimination: What Phase I Communities Are Doing to Address the Problem
Minimizing the potential pathways for contaminants carried in runoff is a key way to control pollutant discharges from MS4s. Include a program to prevent or reduce pollutant runoff from municipal operations into the storm sewer system.
- Pollution Prevention/Good Housekeeping Fact Sheets —Describes BMPs that can be used to prevent pollution from entering MS4s.
- Pollution Prevention/Good Housekeeping for Municipal Operators
- Municipal Pollution Prevention/Good Housekeeping Practices Manual —Focuses on control and reduction of stormwater pollution and addresses local subwatershed restoration goals and objectives.
- Deriving Reliable Pollutant Removal Rates for Municipal Street Sweeping and Storm Drain Cleanout Program in the Chesapeake Bay Basin —Provides information to support pollutant removal efficiencies for Phase I and II communities in the Chesapeake Bay watershed.
Managing stormwater after construction activities end is a key part of the SWMP. Include a program to reduce pollutants from new development and redevelopment projects that disturb ≥ 1 acre of land.
- Post-Construction Fact Sheets
- Post-Construction Stormwater Management in New Development & Redevelopment
- Managing Stormwater in Your Community: A Guide for Building an Effective Post-Construction Program — Provides practical guidance and downloadable tools that can help with program implementation.
- Managing Urban Runoff — Provides technical information on controlling urban nonpoint source pollution.
- Incorporating Environmentally Sensitive Development into Municipal Stormwater Programs — Discusses encouraging or requiring low impact development (LID) practices to meet stormwater goals.
- Urban Stormwater Retrofit Practices Manual — Highlights practices that capture and treat runoff before it is delivered to water bodies.
- Reducing Stormwater Costs through Low Impact Development (LID) Strategies and Practices — Compares the economic viability of LID practices and traditional stormwater management design practices.
- Monitoring to Demonstrate Environmental Results: Guidance to Develop Local Stormwater Monitoring Studies Using Six Example Study Designs (PDF) — Provides study designs for MS4 communities to use to assess their local stormwater programs.
- Green Infrastructure – Provides information on green infrastructure practices that use vegetation, soils, and natural processes to manage water and create healthier urban environments.
- Stormwater Wet Pond and Wetland Management Guidebook —Discusses inspection and maintenance practices at existing ponds and wetlands.
An informed and knowledgeable community is crucial to the success of your SWMP. Implement a public education program on the impacts of stormwater that includes steps to reduce pollutants in stormwater runoff.
- Public Outreach Fact Sheets
- Public Education & Outreach in the Menu of BMPs
- Getting In Step: A Guide for Conducting Watershed Outreach Campaigns —Describes tools for developing and implementing an effective outreach plan.
- Getting In Step: Engaging and Involving Stakeholders in Your Watershed —Describes tools for effectively identifying, engaging, and involving stakeholders throughout a watershed.
- Nonpoint Source (NPS) Outreach Toolbox —Provides educational materials and other useful links for educating the public on NPS or stormwater runoff.
The public can provide you with valuable input and assistance in developing, implementing, updating, and reviewing your SWMP. Include efforts to reach out and engage all economic and ethnic groups in your public participation program.
Provide measurable goals in your SWMP so you can evaluate the program’s effectiveness and make adjustments as necessary. As part of the program, compile a report on program progress that includes things like the status of compliance with permit conditions, results of any information collected and analyzed, summaries of planned stormwater activities, and any changes that have been made.
- Evaluating the Effectiveness of Municipal Stormwater Programs
- Three Keys to BMP Performance: Concentration, Volume, and Total Load
- Measurable Goals Guidance for Phase II Small MS4s —Designed to help operators of small MS4 comply with the measurable goals permitting requirements.
Know whether your storm drain system discharges to an impaired water body or a water body with an approved Total Maximum Daily Load (TMDL). Include a process in your SWMP for addressing the TMDL if necessary.
- Understanding Impaired Waters and Total Maximum Daily Load (TMDL) Requirements for Municipal Stormwater Programs —Discusses how to determine if your MS4 discharges to an impaired water body and how to upgrade your SWMP to address the TMDL.