Floodplain Mapping Update Program Frequently Asked Questions

Floodplain Remapping Project Frequently Asked Questions

Additional questions about flood insurance, the CHAMP program, and floodplains are listed on the following pages and are accessible using the menu on the right:

Frequently Asked Questions

It is absolutely possible for a person to live in the floodplain their entire life and never experience a major flood event. The event that the county is required to regulate to is the 1% annual chance event, or the “100-year” flood event. This is not a flood that occurs once every 100 years, but rather is an event that has a 1% chance of occurring in any given year. Such a flood can happen two years in a row, or not for 200 years.

During the 2013 flood, many places in Boulder County actually experienced less than a 100-year event. Because the maps are meant to predict future flood risk for the 100-year event, it is logical that a property that experienced a smaller flood in 2013 would not have been impacted.

The CHAMP floodplain models are being developed based on the topography of the area as it exists after the 2013 flood event, so predicted risk is based on post-flood conditions that are in many places very different than prior to and that were controlling during the 2013 flood.

Lastly, the floodplain models do not take random events such as debris blockages into account.

The Board of County Commissioners has approved incorporation of the CHAMP Phase I draft maps into the Boulder County Floodplain portion of the Floodplain Overlay Zoning District. This update was effective as of June 1, 2017. The CHAMP Phase II draft maps were approved for incorporation in July 2018 and became effective on August 1 and October 1, 2018.

Both Phase I and II floodplain maps are expected to become effective FEMA Flood Insurance Rate Maps (FIRMs) by 2021.

Throughout the outreach period, the Floodplain Management Team recorded all mapping-related comments that were received and shared them with the CHAMP team. The CHAMP team took these comments into consideration and provided responses to those that were technical in nature. All such comments and responses were published in the staff reports for the Planning Commission and Board of County Commissioners public hearings. If you did not hear directly from county or CHAMP staff about your specific comment, you can view the comment and responses within these documents.

There are different options at various points in the process:

  • Early in the process, when draft maps are first received by the county and are presented at public meetings and online, property owners can contribute information and concerns that will be provided by the county to the CHAMP team of engineers for their consideration.
  • Once the draft maps have been adopted into the Boulder County Floodplain Overlay District, residents may request a change through the comprehensive rezoning process outlined in the Land Use Code Section 4-1100.
  • After FEMA has delivered preliminary Flood Insurance Rate Maps (FIRMs) to the county, there will be a formal 90-day FEMA comment and appeal period when property owners may submit: 1) comments; or, 2) technical data in support of an appeal challenging the preliminary FIRM floodplain data and delineations. Local resources and guidance on how to follow FEMA’s procedures for submitting comments and appeals will be available when this process begins in Boulder County.

Sometimes homes and other structures that are included within the regulatory floodplain boundaries are actually built above the mapped flood elevation. If you can demonstrate your home is on higher ground, you may submit property and elevation materials to FEMA in support of a request for a Letter of Map Amendment (LOMA) to remove the property from the floodplain. There is no cost for FEMA to review your request; however, the requester is responsible for any costs involved in collecting the supporting data necessary to submit an application. A licensed surveyor or engineer is typically required to complete the application and provide elevations for the property.

Keep in mind that even after submitting the application, the LOMA determination may show that the property is not higher than the predicted 100-year flood elevation. The requester may still be required to purchase flood insurance.

Flood insurance rates are impacted when new FEMA maps become effective or when a specific property or area receives approval for a Letter of Map Change. The current CHAMP study is a flood study through which new FEMA maps will be produced, but the final mapping is not expected for several years. The adoption of best available data into the Floodplain Overlay District is for regulatory purposes and does not impact FEMA flood insurance policies.

If your home is newly mapped into a flood hazard area with the CHAMP study, it is recommended that you consider purchasing flood insurance. Lower rates are available for individuals who purchase flood insurance policies prior to the FEMA maps becoming effective.

Contact Us

Floodplain Administrator Contact

Floodplain Administrator


Floodplain Remapping Program Contact



2525 13th Street
Boulder, CO 80304

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Boulder, CO 80306