Do I need a permit for garage conversion in Littleton?

Most likely yes. Garage conversion usually requires a permit in Colorado. Confirm the specifics with Littleton.

Colorado has no statewide building code. Building codes are adopted and enforced by each city or county, and some jurisdictions have adopted none; where that happens the state adopts codes only for hotels, motels, and multifamily buildings, not single-family homes. Colorado law requires any city or county that adopts or updates a building code after July 1, 2026 to adopt the state Model Low Energy and Carbon Code or a stricter one, so insulating the new living space follows the energy code your jurisdiction has adopted. Electrical and plumbing work need their own permits. The state Electrical and Plumbing Boards (DORA) issue permits and inspect where a city or county has no electrical or plumbing inspection program; where it does, the local office issues them. Turning a garage into a bedroom, living room, office or apartment changes it to habitable space, which must meet the code for living areas, such as insulation, heating, ceiling height, light, and an emergency escape opening in any sleeping room. A conversion normally needs a building permit, and often electrical, mechanical and plumbing permits too. Zoning may also require you to keep off-street parking or limit a second unit, so check zoning before you design.