Floodplains Management

Jefferson County Floodplains header

Colorado winter storms and heavy rains have a big impact on flood potential. A floodplain is an area near a water source that is at a greater risk of being covered by flood water.

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Take a look at the Floodplains FAQ and the Jefferson County Floodplains brochure (PDF) for answers to some of the most frequently asked questions.

Floodplain Development Permits

A floodplain development permit must be obtained before doing any work within the floodplain overlay district. Floodplain Development Permits are accepted through the Online Application system. A signed application (PDF) is still required to be uploaded with the online application. If wetlands are present, a permit must be obtained from the US Army Corps of Engineers. Depending on the work within a floodplain, a floodplain study by a Professional Engineer licensed in Colorado may be required with the permit application. A Letter of Map Amendment or Letter of Map Revision Based on Fill through FEMA may also be required depending on the type of work. Please refer to the Floodplain Overlay District Section 37 (PDF) of the Zoning Resolution and the Storm Drainage Design and Criteria (PDF) for more information on Floodplain permits in Jefferson County.

The Local Flood Hazard

The local flood hazard is discussed in detail in FEMA’s January 20, 2019 Flood Insurance Study (FIS). Read a portion of the FIS, including the Community Description and Principal Flood Problems.

Floods are one of the most common hazards in the United States. However, all floods are not alike. Riverine floods develop slowly, sometimes over a period of days. Flash floods can develop quickly, sometimes in just a few minutes, without any visible signs of rain. Flash floods also often have a dangerous wall of roaring water that carries a deadly cargo of rocks, mud and other debris, which can sweep away many things in its path. Overland flooding occurs outside a defined river or stream, such as when a levee or dam is breached. Flooding can also occur from a dam break producing effects similar to flash floods. Be aware of flood hazards no matter where you live, but especially if you live in a low lying area, near water or downstream from a dam. Even very small streams, gullies, creeks, culverts, dry stream beds or low lying grounds that appear harmless in dry weather can flood.


Planning and Zoning staff can answers questions related to floodplain management, including determining if a property is located within a floodplain within Jefferson County. Copies of elevation certificates can be obtained on the Floodplains Elevation Certificates page or by contacting the Planning and Zoning Division.

Contact & FAQs

For additional floodplain information or questions please contact the Jefferson County Planning and Zoning Division at 303-271-8700. In addition, see our FAQs regarding floodplains in Jefferson County.

Map of the Local Flood Hazard

Planning and Zoning staff can answers questions related to floodplain management, including in determining if a property is located within a floodplain within Jefferson County. In addition you can access the Jefferson County interactive mapping application.

Flood Warning System


The most comprehensive weather information is obtained by listening to a NOAA Weather Radio. Weather Radio is operated by National Weather Service offices across the country and broadcasts frequently updated recordings containing current high climatological data. During threatening weather, live broadcasts issue warnings for winds, large hail, tornadoes, flash floods and winter storms. You can purchase a tone-alert NOAA Weather Radio at many local electronic stores.

Emergency Alert System (EAS)

The Emergency Alert System (EAS) is one tool that Jefferson County can use to warn its citizens in case of an impending disaster on participating radio and television stations. In most cases however, the National Weather Service has already activated EAS.

Reverse 911 & Other Local Media

The other system we use more regularly is commonly referred to as “reverse 911”. To ensure that you phone number is registered to your home address for targeted emergency calls, please visit the Jefferson County Sheriff’s Office LookoutAlert page.

We also regularly use other means of local media to put out critical information such as evacuation orders, sheltering information and other emergency messaging.