How to Choose an ADU Contractor in Colorado (Questions to Ask)
How to hire an ADU contractor in Colorado, the questions to ask, the red flags to avoid, how licensing works here, and modular versus site-built compared.
HB24-1152 made ADUs legal on most single-family lots — but the numbers that decide whether one pencils are still set locally. Every figure here is read from the codified ordinance, sourced and dated.
In HB24-1152 subject jurisdictions — municipalities of 1,000+ in metro areas — one ADU must be allowed by right on any lot with a single-family home, owner-occupancy can no longer be required for long-term-rental ADUs, and parking minimums are limited. Cities still set the numbers that matter: size caps, short-term-rental treatment, design standards and fees.
These pages carry each city’s own verified figures, sourced to the ordinance section that sets them. More cities publish as their figures verify. Not listed yet? The statewide ADU calculator works for any Colorado address.
30 jurisdictions are certified ADU Supportive by the Division of Local Government, which makes their residents eligible for CHFA’s ADU interest-rate buydown and credit enhancement through participating lenders: Adams County, Berthoud, Boulder, Brighton, Center, Commerce City, Cripple Creek, Erie, Fort Collins, Fruita, Grand Junction, Idaho Springs, Lafayette, Lake City, Larimer County, Longmont, Louisville, Loveland, Lyons, Monument, Palisade, Ridgway, Salida, Sheridan, Silverton, Superior, Timnath, Westminster, Wheat Ridge, Windsor.
Source: DLG ADU Supportive jurisdictions list; CHFA ADU Finance Programs. The list grows as jurisdictions apply.
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Data as of September 5, 2026. Sources: Colorado DLG, DOLA Division of Property Taxation (TY2026), CHFA, county assessors as cited on each city page, HUD FMR. Olerra pricing: published all-in project ranges, September 2026.
Yes, in most of the state's populated areas. Since June 30, 2025, HB24-1152 requires subject jurisdictions — municipalities of 1,000 or more in metropolitan areas — to allow one accessory dwelling unit by right on any lot with a single-family home. Outside those jurisdictions it depends on the local code. Each city still sets the size caps, setbacks, height limits and short-term-rental treatment that decide what you can actually build; those are listed city by city above.
Yes. An ADU is a new dwelling unit, so every Colorado jurisdiction requires a building permit, plus whatever zoning or site-plan review the local code calls for, before construction starts. Permit fees and review times are set locally and vary widely, so confirm both with your city's planning department. A factory-built ADU is not an exception: it is inspected to the same building code as a site-built home and still needs local permits. Olerra's all-in pricing includes permitting.
In an HB24-1152 subject jurisdiction, one ADU is allowed by right on a lot with a single-family home, so the question becomes what fits rather than whether it is permitted. Lot size, setbacks, height limits and the local size cap decide that. Find your city above for the exact figures, or run a free property check and we will confirm against your parcel.
A one-off site build with a general contractor typically runs about $500,000 to $650,000 for a roughly 490 sq ft unit. Olerra's factory-built Flex Flats run $300,000 to $365,000 for the 490 and $420,000 to $465,000 for the 735, all-in — site preparation, foundation, utility connections and permitting included. Local permit fees, utility tap fees and site conditions are what move the number most between cities.
Residents of the jurisdictions the Division of Local Government has certified ADU Supportive are eligible for CHFA's ADU finance programs, which combine an interest-rate buydown with a credit enhancement through participating lenders. The certified list is on this page. Elsewhere, owners typically use a renovation or construction loan, a home equity line, or a cash-out refinance. This is general information rather than financial advice; your lender will tell you what you qualify for.
An ADU raises your assessed value, and the bill depends on your local mill levy. Colorado assesses the school and local-government portions at different rates for tax year 2026, 7.05% and 6.80% respectively, and subtracts an exemption of 10% of the first $700,000 of actual value from the local-government portion. Each city page here shows the local mill levy and the resulting cost per $100,000 of added value.
Guides and real Colorado numbers from our team — a fresh pick every couple of weeks, or search for exactly what you need.
How to hire an ADU contractor in Colorado, the questions to ask, the red flags to avoid, how licensing works here, and modular versus site-built compared.
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Planning estimates, not quotes or legal advice. Rules, fees, levies and rents change — confirm with your city and lender before committing. Olerra pricing: published all-in project ranges, September 2026. Corrections: sales@olerra.com.
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