Floodplain Ordinance

The City's Planning and Zoning division reviews and updates the building codes for the floodplain areas along the Big Sioux River. These updates will have an impact on construction activities for both new and existing properties located within the floodplain. If you're looking for more information about floodplains, you can find it here. 

It's important to note that these changes will not affect your homeowner or flood insurance policies, nor will they modify the FEMA floodplain map. The proposed updates are general recommendations and are being made available for public review.

More information about floodplains can be found here

Full Updated Floodplain Ordinance

The City of Sioux Falls adopted these regulations on July 6, 2021 and they became effective on July 30, 2021.
Changes include, but are not limited to:

  • Base-level engineering: The City would like to be able to use accurate data to identified floodplains earlier in the FEMA map process. These areas are typically the areas leading into floodplains along smaller tributaries going into the Big Sioux River or other waterways in the area.

  • Substantial improvement: The City would like to track improvements to structures over 3 years (starting in 2023) so that any major improvement or repair (over 45% of the value of the building) would need to meet current standards.
    Example: A house was repaired for tornado damage, and then flood damage the next year. If the combined cost of both projects were worth more than 45% of the value of the building, the building will need to be razed or rebuilt.

  • Freeboard: The City would like to provide an additional level of protection to properties by increasing the minimum height above the flood level from 2 to 3 feet. This increase will help keep properties safer during events and help keep properties above the flood level after future map updates that may increase the elevation of the flood level. This is only applicable to new or substantially improved buildings.

  • Comp Storage: The City would like to protect the water storage areas that happen during a flooding event by not allowing areas to place new fill, but by moving these areas to another site within the same general area.
    Example: If a property owner wanted to raise an area for a new garage, they would be required to provide an area of the same size in the same neighborhood (on their property or if they have an agreement to another property.

Full list of 2021 changes

New regulatory floodplain based on newer FEMA technology and modeling (Base Level Engineering)

The City will be looking to add the use of Base Level Engineering data to include new areas into the regulatory floodplain that are not already included. 

Compensatory storage requirement:

The City is looking to project against filling in the regulated floodplain by requiring that for every cubic foot of fill proposed that at least one cubic foot is excavated within the same general area. 

Redefining Substantial Damage and Substantial Improvement from 50% to 45% and limited based on the total over 3 years:

The City is looking to reduce the amount of improvements that can happen as an improvement or repair in an effort to get more properties into compliance with the current ordinance. The 3-year cumulative calculation would start at $0.00 for all properties and is proposed to start for any permits issued after December 31, 2022.

Accessory Structure allowed within the floodplain to be wet-flood proofed:

The City is looking to allow accessory structures of less than 10% the value of the main structure or 600 square feet (whichever is less) to be placed within the floodplain provided they meet the standards set intended to help the structure from floating away or having walls cave in. 

Elevated buildings will be required to file non-conversion agreements:

The City would like to protect subsequent property owners by requiring an agreement be filed with the register of deeds office to indicate which portion of a building cannot be converted to another use. This is typically only used when a house is built on top of a garage so that the main portion of the house is above the floodplain. 

Floodplain Development Permit fee change from $50 to $75:

The typical cost in staff time and materials for a floodplain development permit varies by each permit but typically that amount is closer to $110.00 per permit. Permits for zoning projects such as decks, sheds, and fences would not be required to pay a fee. A floodplain permit is still required for zoning projects. 

Restriction of temporary storage in the regulated floodplain:

The City would start to permit and limit temporary storage of materials within the regulated floodplain so that any storage pile was restricted in time and had a plan in place to move the materials in the event of an impending flood.

Allow crawlspaces within the regulated floodplain:

The City would start to allow crawlspaces to be used to elevate houses a minimum of three feet above the Base Flood Elevation. 

Restrict fill within the regulatory floodway:

The City would start to limit nearly all fill within the regulated floodway (the floodway is the area of a water channel that experiences the fastest waters during a flood event).

Restrict new hazardous material sites:

The City would limit any new hazardous material sites (such as chemicals, explosives, gasoline, propane, etc.) to areas located outside the 0.2% annual chance floodplain (500-year). No existing businesses would be required to move unless substantially improved or damaged. 

Restrict new critical facility sites:

The City would limit any new hazardous material sites (such as fire stations, schools, nursing homes, hospitals, etc.) to areas located outside the 0.2% annual chance floodplain (500-year), unless the site can meet specific conditions. No existing critical facility would be required to move unless substantially improved or damaged. 


Frequently Asked Questions

Why is this happening?

This is an effort by the City of Sioux Falls to help provide extra protection to properties developed within the City and to help reduce flood insurance costs for those properties that are required to have coverage.

Will this affect my property values and home insurance?

Any updates to the city floodplain ordinance aren’t expected to directly affect property value because no new restrictions are planned to be created. Home insurance rates are also expected to remain the same, regardless of any changes made.

Why is this important?

The goal of these new changes is to provide protection and overall cost savings for new and future property owners.