Floodplain Management Program

New Floodplain Maps Timeline and Additional Details

The Discovery process identifies areas of flooding concern and helps to establish a community's highest priorities. Discovery also identifies opportunities for moving mitigation beyond planning and into action.

Floodplain Ordinance Changes

Changes are effective as of July 30, 2021

Check to see if your property is in the floodplain

Search Your Address for Flood Risk

Flood Gauges in real time

(images are not in real time*) 

*Image source, Google Maps, Street view.

Floodplain Permits

If a permit is required it costs $75 per permit. It is possible to have multiple properties on one permit for floodplain.

We review plans for items from grading to building, issue floodplain permits, and track for compliance with FEMA regulations. This can include, but is not limited to:

  • Review applications and issue permits.
  • Interpret the boundaries of Flood Hazard Areas.
  • Use best available data when Base Flood elevations are not provided.
  • Determine substantial improvement/damage
  • Interact in variance appeal processes
  • Notify adjacent communities, the State, and the Administrator of Alteration or Relocation to the water course.
  • Ensure Maintenance of Watercourse
  • Conduct inspections
  • Investigate complaints of Code Violations
  • Coordinate Map Amendments and Appeals
  • Maintain for Public inspection all flood permit records i.e. Amendments, Revisions, Fill, Certificates, Elevation
  • Certificates and No-Rise Certificates
  • Maintain Floodplain Maps and Flood Data
  • Maintain and update the Floodplain Management Ordinance
  • Prepare and submit biennial reports”
To ensure that the safety of the general public and properties along the floodplain are protected to the greatest extend possible.”

The City of Sioux Falls limits development in floodplains and for all lots since August 25, 2016 within one hundred feet of the regulated floodplain. Any property within the floodplain is not allowed to build in the floodway and is required to be at least two feet above the Base Flood Elevation (BFE) for any part of the building not to be used for cold storage. Any storage areas with an elevation below BFE are required to have openings and are designed for water flow and damage. Some types of buildings are restricted from this area, they include hospitals, fire stations, nursing homes, schools, etc. For areas within one hundred feet of the regulated floodplain and platted since August 25, 2016 residential buildings are limited to having basements no closer than twenty feet from the edge of the floodplain, basement depth of no more than five feet lower than the BFE, and the lowest opening such as doors or windows to the outside no less than one foot above the BFE. These standards are designed to provide additional protections for these properties.

In Addition to these restrictions the City also has limits for substantial damage and improvements. These are applicable to all property within the regulated floodplain are intended to help owners make an educated decision when it comes to financially investing or reinvesting in a property. Once a property has been declared substantially damaged or improved the entire structure will need to come up to the current standard, usually this means raising the building up so that the floor is at least two feet above the BFE.

Substantial damage is when a building gets damage from any source (fire, air plan, flood, etc.) and the cost of repairing that damage is equal or greater to 45%, and starting in 2023 that limit will be for over a three-year period.

Substantial improvement is when a building gets permits to make improvements in the building (addition, deck, roof, siding, remodeling, etc.) and the cost of the improvement is equal or greater to 45%, and starting in 2023 that limit will be for over a three-year period.

If you have questions regarding  a property and substantial improvement or damage please feel free to reach out to us at floodplain@siouxfalls.org.

Frequently Asked Questions

A flood is an event where water temporarily newly covers two or more acres or affects two or more properties. Usually caused by river runoff or local rain events. 
The Big Sioux River and Skunk Creek are the two primary flooding sources affecting the City of Sioux Falls. The Big Sioux River upstream of Sioux Falls has a drainage area of 5,718 square miles. Skunk Creek is a tributary to the Big Sioux River and has a drainage basin of 570 square miles upstream of Sioux Falls.
Since 1881, the City of Sioux Falls has experienced flooding from the Big Sioux River 19 times and from Skunk Creek 8 times. Various other events have happened over the year due to localized buildup during heavy rain events. Updated December 2019.
Most flooding events occur during the months of March and April and are caused by snow melt. Flooding caused by rainfall historically has occurred during the month of June.
While any area can flood, the most common areas to flood are identified as a floodplain. The areas subject to flooding are shown on FEMA’s Flood Insurance Rate Maps (FIRM) and shown on City of Sioux Falls maps available online.  Flood Insurance Rate Maps (FIRM) are available for downloading here.
January 17, 1979, the most current FEMA maps are dated October 5, 2017; although different areas of the City have different effective map dates.
Flood risk can change over time due to a variety of factors.  Floodplain maps are occasionally updated to reflect these changes. Typically, when a property is removed from the floodplain no property-specific notices are sent out. When properties are added to the floodplain a notice is typically mailed out ahead of the effective date of the map. Depending on the scale press releases, media coverage, and/or community meetings may also be used.
It depends on what the property is being looked at for. Just because the property is considered within a floodplain in one does not mean it will be considered in the floodplain for both.
For mortgages and insurance, the lending institution will make the determination. 
For building and code concerns, the City of Sioux Falls will make the determination. 

Property owners need to contact their lender directly for exact details, but generally, a detailed survey is needed (at the property owner’s expense), then those details (via an Elevation Certificate) can be sent in to FEMA via an online account by the homeowner, surveyor, or third party. FEMA will review the information and provide a letter (Letter of Map Amendment - LOMA) within 90 days that could either remove the structure, portion of the property, whole property, or not remove anything. That letter (LOMA) can be provided to the lender for flood insurance reconsideration. Please note that the lender still has the authority to require flood insurance even if FEMA provides a letter. Additionally, this letter (LOMA) automatically gets reviewed every change new maps are adopted by FEMA within the community. Changes to the floodplain may result in letters becoming void in the future.

Detailed information from a registered professional can be submitted to the City to show the building and/or property’s location in comparison to the floodplain. This could be an Elevation Certificate (EC), site plan, or other professional analysis. The City of Sioux Falls may require additional details to evaluate the request and reserves the right to continue to consider the property within the floodplain.

Pre-FIRM buildings are those built before the effective date of the first Flood Insurance Rate Map for a specific area; Along the Big Sioux River and Skunk Creek therefore, pre-firm is prior to January 17, 1979.

Post-FIRM buildings are those built after the effective date of the first Flood Insurance Rate Map for a specific area; Along the Big Sioux River and Skunk Creek therefore, pre-firm is prior to January 17, 1979.

Elevation Certificates are required for most Post-Firm Buildings. The elevation certificate provides the data that verifies compliance with the floodplain ordinance.

In support of the National Floodplain Insurance Program (NFIP), FEMA identifies flood hazard areas throughout the U.S. and it's territories by producing Maps (such as the Flood Insurance Rate Maps – FIRM’s). Areas of flood hazards are identified on these maps, including the floodway (where fast-moving water occurs during a flood event) and the flood fringe (where water generally sits still during a flood event). Together the floodway and flood fringe are commonly called the floodplain.  This floodplain is considered a high-risk area having a 1-percent chance of occurring in any given year and is commonly referred to as the Special Flood Hazard Area (SFHA).

Additional building restrictions and standards are required in and within 100’ of this area. Flood insurance is required in this area for properties with a federally backed mortgage. 


In addition to the required flood insurance by a lender for a federally backed mortgage, any property with floodplain can expect additional building code standards and restrictions for any development (building, repair, concrete work, grading, etc.). Pre-FIRM properties have separate standards that once exceeded may cause the property to have to be brought into current ordinance compliance (typically raising the house, razing, or moving).   

Any plat for a property within the floodplain should expect to see the floodplain boundary on the plat. 


A floodplain development permit is required to be submitted on any development within a special hazard area. The floodplain management ordinance addresses hazard reduction through general standards, specific standards and subdivision standards. 

Development is considered any change to the property. Some examples are, but not limited to, new buildings, remodels, demolition, lot grading, underground work, paving, placement of signs, etc.


 Simply put, it’s how high is water expected to get during a flood. More specifically, it’s the water surface elevation of the one (1) percent annual chance flood. The height in relation to mean sea level expected to be reached by the waters of the base flood at pertinent points in the floodplains of coastal and riverine areas. Please note, no two flood events are the same. As such the water levels of different floods will be different between each event.

The City of Sioux Falls does not require an elevation certificate with all building permits. Elevation certificates are required for properties within the floodplain and for residential properties built within one-hundred (100) feet of the floodplain.

For the City of Sioux Falls this “Grandfathering” means that a property was built to code at the time of construction. However, properties are only allowed to continue to not meet current floodplain standards for as long as they are not substantially improved or damaged. Once that happens the entire structure needs to be brought up to current floodplain standards immediately. 

By ordinance substantial for floodplain needs is forty-five (45) percent of a structure’s value (land value cannot be included). 

Improvements represent things like remodeling, additions, etc. to the building. 

Damage represents repairs needed to bring the building back to the pre-damage condition. Very important note here is that the source of damage (fire, flood, car crash, etc.) doesn’t matter. 


 No, with FEMA’s Risk Rating 2.0 program elevation certificates are no longer required for insurance. The insurance agent will need some information from the property but hiring a registered professional likely is not needed anymore. 

About the National Flood Insurance Program. Frequently Asked Questions. Federal Emergency Management Agency. Floodsmart.gov


Flood insurance is different than homeowners insurance because homeowners insurance excludes flood damage. Flood insurance is available to all properties within the City of Sioux Falls because the City participates in the National Flood Insurance Program. Your policy may be eligible for a discount because the City also participates in the Community Rating System. Any flood insurance needs to be in place at least 30 days before a flood event in order to put in a claim.

Insurance costs will be based on risk rating 2.0, more information on this method of determining flood insurance costs can be found at https://www.fema.gov/flood-insurance/risk-rating

Insurance coverage is limited to specific basement items that are not furniture and cleanup. A more detailed explanation can be found via FEMA’s website

Regular maintenance of property and drainage systems can be key to preventing or limiting flooding during an event. Look around your property and neighborhood and work with neighbors to identify where excess rain and snowmelt will likely go and see if there are any spots that may cause private property damage along the way. For your own property check to make sure things are secured to your house correctly so that they don’t get blown away in a high wind event, check that downspouts are far enough away from your house that water won’t be forced to sit next to your foundation for any periods of time.

More substantial modifications could be necessary to protect your structure from flooding. You can always reach out with questions to our floodplain team at floodplain@siouxfalls.org and we may be able to provide some guidance including when a permit for floodplain or building improvements may be needed. Some examples of projects that may need permitting are: installing a berm, regarding the property, replacing windows and doors with more flood resistance versions, or even elevating the structure. FEMA offers a detailed look into 6 ways to protect your home from flooding in THIS PDF guide.

For temporary emergency modifications generally you can start the installation immediately without a permit. Please feel free to reach out to verify if your temporary project meets the criteria for this emailing our floodplain team at floodplain@siouxfalls.org. Some examples of temporary projects that may be needed to prevent flooding are: installing a temporary berm, stacking sandbags or other water barrier options, temporary sealing building openings, or even elevating major appliances. A PDF FEMA guild can be found online HERE.

If you notice any illegal dumping in the drainage areas you can report it. You can use an app or the City’s website at: https://www.siouxfalls.org/contactus/public-works/engineering Select “Drainage Concerns” and then select the area and add any pictures or comments and send it in. You can also go below the map and submit text only information instead.

The floodplain function in the Sioux Falls area can be summarized in the following categories from A Unified National Program for Floodplain Management, 1994, p.41:

Water Resources:

  • Natural Flood & Erosion Control
    • Provide flood storage and conveyance
    • Reduce flood velocities
    • Reduce flood peaks
    • Reduce sedimentation
  • Surface Water Quality Maintenance
    • Filter nutrients and impurities from runoff
    • Process organic wastes
    • Moderate temperature of water
  • Groundwater Recharge
    • Promote infiltration and aquifer recharge
    • Reduce frequency and duration of low surface flows

Biologic Resources

  • Biological Productivity
    • Support high rate of plant growth
    • Maintain biodiversity
    • Maintain the integrity of the ecosystem  
  • Fish and Wildlife Habitats
    • Provide breeding and feeding grounds
    • Create and enhance waterfowl habitat
    • Protect habitats for rare and endangered species

Societal Resources

  • Harvest of Wild & Cultivated Products
    • Enhance agricultural lands
    • Provide sites for aquaculture
    • Restore and enhance forest lands 
  • Recreational Opportunities
    • Provide areas for active and passive uses
    • Provide open space
    • Provide aesthetic pleasure
  • Areas for Scientific Study and Outdoor Education
    • Contain cultural resources (historic and archaeological sites)
    • Provide opportunities for environmental and other studies

The City has different policies to help with different aspects of these areas, but the floodplain program implemented the compensatory storage requirement to address many of these issues, while our parks departments have provided great open space and natural areas along waterways in the City, and in addition, the Engineering department has provided many new areas for collection, saturation, and through more natural maintenance techniques provides for the natural filtration of water before it enters the stream.

Avoid Active Flood Areas


Email All of Us: Floodplain@siouxfalls.org

Floodplain Administrator: Butch Warrington

Main Contact: Albert Schmidt (CFM)
Phone: (605) 367-8603

Additional Contacts: Mariah South (CFM)