Defensible Space and Home Ignition Zone Aerial Photo 

Your Wildfire Defensible Space

The Boulder County Land Use Department is providing an aerial photo of wildfire defensible space zones for mountain residents. This photo is offered as an educational tool to help residents prepare for future wildfires.

To view your Wildfire Defensible Space photo, enter your property address in the Address search box below and click Submit. On the photo you will see concentric circles that show the rough boundary of your defensible zones 1 and 2. Zone 1 highlighted in red extends 30 feet from your building footprint. Zone 2 highlighted in yellow extends 100 feet from your building footprint. This drawing is for informational purposes only. If you live on a slope you will need to extend each zone on the downhill side of your home.

For help in evaluating your Wildfire Defensible Space photo, view the "Your Wildfire Defensible Space" PDF (or slideshow at the bottom of this page), or contact the Wildfire Mitigation Team at 303-441-3930 or

After reviewing your photo, please visit our Wildfire Mitigation Education and Outreach Portal to learn detailed information about how to create defensible space and maintain effective wildfire mitigation on your land.

 Your Wildfire Defensible Space FAQ

What is defensible space?

Defensible space is an area between a house and an oncoming wildfire where the vegetation has been managed to reduce the wildfire threat and allow firefighters to safely defend the house. In many cases creating effective defensible space requires working with neighbors.

What is the home ignition zone?

The home ignition zone is the area of the home and its immediate surroundings. It includes both your home and your defensible space.

Does defensible space affect my property assessment?

No, defensible does not impact the County’s valuation of your home.

What is the date of the aerial photo of my property?

The aerial photos were taken during the spring and summer of 2012.

Why are the buildings on my property not drawn correctly (some are missing or it’s not my building)?

The Land Use Department has mapped the buildings based on aerial photos. Some features (such as a pool or patio) may have been misidentified as a building. Some buildings may have been modified after the aerial photo was taken. A neighboring building may also have been misidentified as your building. The buildings mapped by the Land Use Department have no effect on how your property is assessed.

How were the lines on the photo marking zones 1 and 2 determined?

The Land Use Department has mapped buildings based on aerial photos from multiple years. The zones were created by drawing a line 30 feet and 100 feet from the edge of the building. These lines do not factor in slope. Property lines are not shown on this map; you can only cut on property you own. 

If these lines identify the minimum defensible space zones, how do I determine the actual zones for my property?

Slope is a topographical feature that has a pronounced influence on wildland fire behavior. In the absence of wind, fires spread more rapidly upslope because the flames are closer to the fuels, thus preheating the upslope fuels and making them more susceptible to spotting from firebrands. As the slope factor (rise over run) increases, the rate of spread and flame length also increases. Homes adjacent to steep slopes require additional distance between fuels to create effective defensible space.

Why do my defensible space zones extend around structures other than my main residence?

In order to protect your outbuildings from wildfire, they also require defensible space. Wildfire may spread from building to building so defensible space around your detached garage or barn will also help protect your home.

Who is responsible for creating and maintaining effective defensible space?

Each and every homeowner is personally responsible for creating and maintaining effective defensible space.

Does Boulder County require homeowners to create and maintain effective defensible space?

Boulder County’s Building and Land Use Codes require individuals who are constructing a new home in forested areas, or remodeling some existing homes, create and implement a Wildfire Mitigation Plan, which includes the creation and maintenance of effective defensible space. Other homeowners are encouraged, but not required, to create and maintain effective defensible space.

As a result of the County’s Site Plan Review process, tree planting and/or preservation was required for my property. Do these requirements still apply?

Yes, you will be able to create effective defensible space and a safe home ignition zone as well as maintain any required screening. If you have any questions about how to accomplish both goals, please use our Ask a Planner form.

Does defensible space affect my homeowners insurance? 

Each insurance company has its own policies and guidelines. Please contact your own insurance company to find out how defensible space affects your insurance.

How can creating and maintaining effective defensible space help my neighbors and community?

Wildfire does not recognize property lines. If you effectively mitigate your property, you may help save your neighbor’s home and vice versa. Wildfires can impact entire communities. Linked defensible spaces are a key community protection strategy. There are specific examples in the Fourmile Fire where a family’s defensible space helped save neighboring homes and strengthen their community.

For more information on wildfire mitigation and forest health, visit the Wildfire & Forest Health page.

 "Your Wildfire Defensible Space" Slideshow


Land Use Wildfire Mitigation

Main: 303-441-3930
Fax: 303-441-4856

Courthouse Annex Building

2045 13th Street
Boulder, CO 80302
8 a.m. - 4:30 p.m. M, W, TH, F
10 a.m. - 4:30 p.m. Tuesday
Plan review services for building permits are not available on Tuesdays.
Building permits can be applied for and issued until 4 p.m.
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Mailing Address

PO Box 471
Boulder, CO 80306