Resources

Official pages worth reading before you hire

Permit offices, the Town's basement guide, radon testing, and where to call before anyone digs.

These are official pages, not pages this site wrote. They were reviewed on November 8, 2026. Departments change handouts. Use the linked page for the current rule, fee, and form. This website is not the building department.

Town of Castle Rock

Addresses inside town limits are permitted by the Town, not by Douglas County.

Adopted building codes. The page says amendments, including the 2024 International Residential Code, took effect for new permit submittals on June 30, 2026.
Residential basement finish guide (PDF). This is the handout that publishes the egress opening, well, room-size, and alarm notes cited on this site. It also says a new opening in an existing basement wall needs a stamped structural plan.
Town permit portal. The basement guide names this portal for applications.
Castle Rock municipal code. Title 15 is where the Town's code amendments live. Read the code rather than relying on a summary.

A different address, a different office

These links are here so a homeowner does not take a Castle Rock handout to the wrong counter. This site does not publish a separate sales page for each city.

Town of Parker Building Division and how Parker accepts permits.
City of Lone Tree Building Division and Lone Tree's permit guide. That guide lists basement finish as work that needs a permit and treats same-size window replacement differently from a larger opening.
Douglas County Building Division permits. This is the counter for unincorporated Douglas County, which includes much of Highlands Ranch. Confirm the parcel.

Radon is a separate question

Finishing a basement is a reasonable time to test for radon. An egress permit does not answer that test.

Colorado Department of Public Health and Environment: testing a home for radon.
CDPHE, January 2026. The department said half of Colorado homes have elevated radon and asked residents to test. A neighbor's result is not your result.
Douglas County radon page. Read it for the current testing notes and any kit offer. This website does not ship kits.

Before anyone digs

A window well means excavation. Utility locate is not a building permit. Call 811, or start at Colorado 811, before digging.

Notes on this site

A comparison of Castle Rock sold prices for 3, 4, and 5 bedroom houses is being researched. It is not published. The notes page will stay empty of figures until that write-up is supplied and checked. This site will not fill the gap with a guessed cost or a guessed payback.