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.
Berthoud’s real rules, taxes and rents — read from the codified ordinance, every figure sourced and dated. Here: ADUs up to 850 sq ft, a HUD benchmark rent of $1,537/mo for a 1-bed. Run your own numbers below, free.
Read from the Berthoud Code Of Ordinances itself — the operative legal text, not a website summary. Berthoud is an HB24-1152 subject jurisdiction: since June 30, 2025, state law requires it to allow an ADU wherever it allows a single-family home, with administrative approval — the local standards below still apply.
| Maximum ADU size | 850 sq ftverified September 2026Berthoud Code Of Ordinances §30-5-109the ordinance textThe total square footage of the accessory dwelling unit shall not exceed 850 square feet. |
| Height limit | Detached ADU in the Urban Residential (UR) district: 25 ft, and no taller than the main home. In R-1 to R-4 and AG districts there is no ADU-specific limit; the 30 ft accessory-building cap applies.verified October 2026Berthoud Code Of Ordinances §30-4-108the ordinance textTable: Urban Residential Dimensional and Bulk Standards, column "Urban Residential Detached House": "Accessory Structure: Accessory Dwelling Unit (ADU)/ Detached Garage"; "Max Height (not to exceed height of primary structure): ADU: 25' / Garage: 17' unless combined with ADU, then 25'". Table: Traditional Residential and Agricultural Standards (R-1, R-2, R-3, R-4, R-5, AG): "Accessory Structure maximum height: 30'" (all six columns). Sec. 30-5-109(E)(2)(c): "The accessory dwelling unit shall be located not forward of the principal dwelling, shall match the design of the principal dwelling, and shall follow the accessory structures setback standards." Sec. 30-5-109(D)(3): "The accessory building shall adhere to the Dimensional and Bulk Standards of this Chapter." |
| Owner occupancy | No — Berthoud's ADU standards contain no owner-occupancy requirementverified October 2026Berthoud Code Of Ordinances §30-5-109the ordinance textSec. 30-5-109(E): "The accessory living area may be occupied by one additional family as defined by this Code, separate from the principal dwelling unit." No part of the ADU standards requires the owner to live on the property. |
| Extra parking | None beyond the main houseverified September 2026Berthoud Code Of Ordinances §30-5-109the ordinance textAccessory dwelling units are exempt from meeting parking requirements addressed in the parking Section of this Code. |
| Setbacks | Detached ADU in the UR district: side 5 ft (one story) or 10 ft (two stories), rear 5 to 8 ft. In R-1 to R-4 and AG districts, accessory buildings sit 5 ft from all property lines. The ADU may not sit forward of the main home.verified October 2026Berthoud Code Of Ordinances §30-4-108the ordinance textTable: Urban Residential Dimensional and Bulk Standards, column "Urban Residential Detached House": "Side Setback: ADU: 5' for one story, 10' for two stories / Garage: 5'"; "Rear Setback: ADU: 5'-8' / Garage: 5'"; "Setbacks for all other Accessory Structures (pools, gazebos, etc.): 5'; however never allowed in an easement". Table: Traditional Residential and Agricultural Standards: "Accessory Structure setback from all property lines.: 5', however never allowed in an easement. Excludes garages with vehicle access on corner side lots, which will follow the regular setbacks of the zoning district". Sec. 30-5-109(E)(2)(c): "The accessory dwelling unit shall be located not forward of the principal dwelling, ... and shall follow the accessory structures setback standards." |
Source: Berthoud Code Of Ordinances, §30-5-109 · ordinance text retrieved 2026-10-08, re-verified October 2026 · open “the ordinance text” under any figure to read the exact sentence it comes from.
Berthoud’s size cap is conditional rather than a single number: 850 — worth reading closely before sizing a unit. No extra parking is required for the ADU.
And Berthoud is one of only 30 Colorado jurisdictions certified ADU Supportive, which makes residents eligible for CHFA’s state-backed ADU financing — an interest-rate buydown and credit enhancement offered through participating lenders. Most of the Front Range doesn’t have this lever.
What an ADU adds to the tax bill in Berthoud, and the federal benchmark for what it rents for.
Levies: Larimer County Assessor - 2025 Mill Levies by Tax Area and Authority (PDF) — example: Larimer County tax area 2400; levies differ between tax areas inside Berthoud; check your parcel with the county assessor. Rates: Colorado DOLA, TY2026 — the 10% reduction on the first $700,000 of value applies to the local-government portion, once per property. Rents: HUD Fair Market Rents, huduser.gov.
Two ways to build the same unit in Berthoud. Both figures are all-in — design, permits, foundation, utility connections and installation.
Published Front Range ranges for a comparable one-off build, 2025–26
≈ $2,100–$2,600 / month fully financed
Fits Berthoud’s size rule
≈ $2,800–$3,500 / month fully financed
Fits Berthoud’s size rule
Olerra ranges: published all-in project pricing, September 2026 — site preparation, foundation, utility connections and permitting included.
Free and specific to you. Want to go further?
Yes. The Berthoud Code Of Ordinances permits accessory dwelling units (§30-5-109), subject to the size, height, setback and use rules quoted above from the ordinance text. Berthoud is also an HB24-1152 subject jurisdiction, so since June 30, 2025 state law requires it to allow an ADU wherever it allows a single-family home, with administrative approval; the local standards above still apply. Zoning district, lot size and setbacks still decide what fits on a specific lot — the free property check confirms yours.
Yes. An ADU is a new dwelling unit, so Berthoud requires a building permit (plus any zoning or site-plan review the code calls for) before construction starts. Olerra's all-in price includes permitting, and factory-built units are inspected to the same building code as a site-built home.
Per the Berthoud Code Of Ordinances: 850 sq ft. Both Olerra Flex Flats — the 490 and the 735 — fit under this rule. The free property check confirms what fits on your lot.
Per the ordinance: No — Berthoud's ADU standards contain no owner-occupancy requirement.
A one-off site build with a general contractor typically runs about $500,000–$650,000 for a ~490 sq ft unit. Olerra's factory-built Flex Flats run $300,000–$365,000 (490) and $420,000–$465,000 (735) all-in — site preparation, foundation, utility connections and permitting included.
Roughly $660 per year for every $100,000 of value the ADU adds, in the example tax area shown above: Colorado's TY2026 school (7.05%) and local-government (6.80%) assessment rates on the latest certified (TY2025) levy, a mixed-year estimate. Levies differ between tax areas, so check your parcel with the county assessor.
Same method, each city’s own ordinance. The Colorado hub lists every city, and the statewide ADU calculator covers any Colorado address.
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 departments and journalists are welcome to reference this data.
Olerra ADU Cost Calculator — Berthoud, CO. Page updated October 9, 2026; rules verified October 2026. https://www.olerra.com/adu-calculator/berthoud/ <a href="https://www.olerra.com/adu-calculator/berthoud/">Berthoud ADU rules & costs</a> Page updated October 9, 2026. The oldest dated figure on the page is from August 25, 2026.
Planning estimates, not quotes or legal advice. Rules, fees, levies and rents change — confirm with the city and your lender before committing. Rules data: codified ordinance as of August 25, 2026, re-verified October 2026. Olerra pricing: published all-in project ranges, September 2026. Corrections: sales@olerra.com.
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