Last Updated 08/04/2026
South Dakota Stormwater Regulations
EPA Stormwater Program Summary – South Dakota
Program Name: South Dakota General Permit for Storm Water Discharges from Small MS4s
Program Status: Existing MS4 Stormwater Program: State-wide general permit and guidance manual issued December 2002; all MS4s to have applied by March 10, 2003.
Regulatory Authority: MS4 General Permit administered by South Dakota Department of Environment and Natural Resources, Surface Water Quality Program as mandated in the Administrative Rules of South Dakota (Chapters 74:52:01 through 74:52:11)
Standard Source: Phase II MS4 general permit
Size Threshold: Projects that disturb a land area one acre or greater, including projects less than one acre that are part of a larger common plan of development or sale (Permit, Section 4.5, pg. 13).
Limited geographic area where standards apply: Regulated MS4 areas (urbanized areas)
On-Site Retention/Volume Control: N/A
Channel protection requirement: N/A
Water Quality requirement: BMPs must minimize water quality impacts. No specific state-wide standards beyond this (Permit, Section 4.5, pg. 13).
Flood control requirement: N/A
Compliance: Standards are reviewed by the MS4 during site plan review at the local level (Manual, pg. 62). Inspection & Maintenance/O&M: The MS4 operator must ensure adequate long-term operation and maintenance of BMPs. MS4s should require that, as part of the plat, it be noted that the legal title holder to the property is responsible for maintaining the BMPs, and that the municipality has the legal right to enforce that obligation, either by legal action to obtain compliance, or by performing the maintenance itself and then collecting those expenses by recording a lien on the property. Post-construction inspection and enforcement programs are required (Manual, pg. 6-4).
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Frequently Asked Questions
Does South Dakota have a statewide post construction stormwater standard?
Not really. South Dakota’s general permit for small municipal separate storm sewer systems (MS4s) requires that best management practices (BMPs) minimize water quality impacts, but it doesn’t set specific statewide numeric standards for on-site retention, channel protection, or flood control. Those specifics are generally addressed at the local level instead, which is why municipal ordinances (like Brookings’) carry more of the detailed design and maintenance requirements.
Who is responsible for maintaining stormwater BMPs long term under South Dakota's program?
The municipality (MS4 operator) is responsible for ensuring adequate long-term operation and maintenance of BMPs, but South Dakota’s guidance directs municipalities to place that obligation on the property owner. This is typically done by noting in the property plat that the legal titleholder is responsible for maintaining the BMPs, and that the municipality has the legal right to enforce that obligation, either through legal action or by performing the maintenance itself and placing a lien on the property to recover the cost. AQUALIS can help property owners understand how their specific municipality has structured this responsibility.
Does South Dakota require ongoing inspection of stormwater facilities after construction?
Yes. Post construction inspection and enforcement programs are a required part of the state’s Phase II MS4 program, and compliance is reviewed by the municipality during site plan review at the local level.
Who needs a NPDES/Surface Water Discharge permit?
There are three types of permits issued out of this program.
- Surface Water Discharge Permit: If pollutants (even heat can be considered a pollutant) are being discharged from a “point source” to waters of the state, a Surface Water Discharge permit is needed. An example of a “point source” would be a pipe or ditch. For information please contact the Water Quality Program in Pierre at (605) 773-3351.
- Pretreatment Industrial Users Permit: A Pretreatment Industrial Users Permit is issued to an industry discharging process wastewater to the sanitary sewer. Aberdeen, Brookings, Huron, Mitchell, Rapid City, Sioux Falls, and Watertown have received delegation of this program. SDDANR issues this permit to industries in other municipalities. For information please contact Kyle Doerr at (605) 773-3351.
- Stormwater Permit: A Stormwater permit is issued to an industry or construction site. This permit requires the source to develop a plan to prevent or reduce runoff of pollutants. For more information on stormwater permits, contact the Stormwater Team by email or by calling 1-800-737-8676 or (605) 773-3351.
Why are National Pollution Discharge Elimination System (NPDES) regulations important?
By 1972, municipal and industrial wastewater pollution of the rivers, streams, and lakes in America had become a national concern. To clean up the nation’s waters, Congress passed the Federal Clean Water Act of 1972. This Act formed the National Pollutant Discharge Elimination System (NPDES) Permit Program. The main goals of the NPDES Program are to control the amount of pollution that can enter waters of the United States and protect the beneficial uses of all streams and lakes. EPA delegated authority for this program to South Dakota on December 30, 1993.
The information on this page is provided for general informational purposes only and is not legal advice. Regulations change frequently — AQUALIS makes no warranty as to the accuracy or completeness of this content, and any reliance on it is at your own risk. Consult a qualified professional or your local regulatory authority to confirm requirements applicable to your specific property.
