Floodplain Mapping Update Program Frequently Asked Questions

The Boulder County Community Planning & Permitting office at 2045 13th St., Boulder is open to the public on Monday, Wednesday, and Thursday from 8 a.m. to 3 p.m., and on Tuesday from 10 a.m. to 3 p.m. Appointments are available on Tuesday but are not required. Schedule an appointment.

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:

More FAQs are addressed in the county’s Preliminary Flood Insurance Rate Map (FIRM) fact sheet.

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 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. In September 2019, FEMA released Preliminary Flood Insurance Rate Maps (FIRMs) based on the CHAMP remapping efforts. The Preliminary FIRMs have many generally small differences from the already adopted draft CHAMP maps, mainly from clean-up and smoothing of boundaries. The Preliminary FIRMs were adopted by the BOCC, replacing the map data, effective, Jan. 10, 2020. This allows County staff to better protect the health, safety, and welfare of the residents of and visitors to Boulder County.

There are different options at various points in the process:

  • Early in the process, when draft maps were first received by the county and were presented at public meetings and online, property owners could contribute information and concerns that were then provided by the county to the CHAMP team of engineers for their consideration.
  • Now that the Preliminary FIRMs 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.
  • 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. We expect the 90-day appeal period to begin in the spring of 2020. More information is available on the county’s appeals webpage.

Throughout the outreach period for draft CHAMP mapping, 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.

Sometimes homes and other structures that are included within the regulatory floodplain boundaries are actually built above the mapped flood elevation that defines the regulatory floodplain near that structure. 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 FIRMs are not expected to become effective until 2021 or later. 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

Community Planning & Permitting - Floodplain Administration

Email: floodplainadmin@bouldercounty.gov


2045 13th St.
Boulder, CO 80302

Map and Directions


8 a.m. to 3 p.m. Monday, Wednesday, Thursday
10 a.m. to 3 p.m. Tuesday

Mailing Address

Community Planning & Permitting
Floodplain Administration
P.O. Box 471
Boulder, CO 80306