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.
Monument’s real rules, taxes and rents — read from the codified ordinance, every figure sourced and dated. Here: rents floored at $1,464/mo. Run your own numbers below, free.
Read from the Monument Code Of Ordinances itself — the operative legal text, not a website summary. Monument is an HB24-1152 subject jurisdiction: since June 30, 2025, Colorado law guarantees one ADU by right on any lot with a single-family home here.
| Maximum ADU size | 600 sq ft, or 50% of the principal structure's floor area if less (standard zones); up to 1,250 sq ft in the Large Lot Residential Districtverified September 2026Monument Code Of Ordinances §18.03.390the ordinance textThe floor area of an ADU shall not exceed fifty (50) percent of the floor area of the principal structure or six hundred (600) square feet, whichever is less. In the Large Lot Residential District the floor area of an ADU may be greater than six hundred (600) square feet, but shall not exceed one thousand two hundred fifty (1,250) square feet. |
| Size relative to the main house | 50%verified September 2026Monument Code Of Ordinances §18.03.390the ordinance textThe floor area of an ADU shall not exceed fifty (50) percent of the floor area of the principal structure or six hundred (600) square feet, whichever is less. |
| Height limit | 16 ft (detached ADU); lesser of the principal building's maximum permitted height in the applicable zoning district or 25 ft (attached/integrated ADU); 25 ft (detached ADU converted from an existing garage)verified September 2026Monument Code Of Ordinances §18.03.390the ordinance textAttached or integrated ADUs shall not exceed the maximum permitted height of the principal building in the applicable zoning district, nor twenty-five (25) feet. Detached ADUs shall comply with the height restriction in the applicable zone district, except that no detached ADU shall exceed sixteen (16) feet in height, unless the detached ADU is created through the conversion of an existing garage, and does not exceed twenty-five (25) feet in height. |
| Owner occupancy | Yes, but only as a one-time check: the owner must demonstrate residency on the parcel at the time the ADU application is submitted, not on an ongoing basis; a distinct rule applies when the ADU is built simultaneously with a new primary dwelling unitverified September 2026Monument Code Of Ordinances §18.03.390the ordinance textThe property owner must demonstrate that the property owner resides on the parcel when an application is submitted: i. To construct or convert an accessory dwelling unit. This exception does not apply for an accessory dwelling unit that is being constructed simultaneously with a new primary dwelling unit. |
| Short-term rental | Noverified September 2026Monument Code Of Ordinances §18.03.390the ordinance textNo ADU or any dwelling unit on the same lot as an ADU may be used for short-term rentals. For purposes of this provision, rental of any dwelling unit for thirty (30) days or less is a short-term rental. |
| Extra parking | 1 additional spaceverified September 2026Monument Code Of Ordinances §18.03.390the ordinance textOne (1) off-street parking space shall be provided for each attached or detached ADU unless the Director of Planning or designee approves an alternative parking arrangement. |
| Setbacks | Rear 5 (detached ADU; lesser of 5 ft or the zone's accessory-structure setback); otherwise same as principal buildingverified September 2026Monument Code Of Ordinances §18.03.390the ordinance textThe minimum rear yard setback for a detached ADU shall be the lesser of five (5) feet or the minimum accessory structure setback established for the zoning district. |
Source: Monument Code Of Ordinances, §18.03.390 · ordinance text retrieved 2026-08-25, re-verified September 2026 · open “the ordinance text” under any figure to read the exact sentence it comes from.
Monument’s size cap is conditional rather than a single number: 600 sq ft, or 50% of the principal structure's floor area if less (standard zones); up to 1,250 sq ft in the Large Lot Residential District — worth reading closely before sizing a unit.
The cap is also relative: an ADU here may not exceed 50% of the main house, so a smaller primary home means a smaller buildable ADU.
The owner must live on the property (main house or ADU) — common across Colorado (11 of the 14 codes we’ve read require it), and the rule that most often shapes rental plans.
Short-term rental of the ADU is not permitted, so the model here is long-term tenancy or family use.
Plan for 1 dedicated off-street space beyond the main house’s parking — on a tight lot, often a bigger siting constraint than the size cap.
And Monument 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 Monument, and the conservative floor on what it rents for.
Levies: El Paso County Treasurer - Mill Levies (2025 Mill Levies.xlsx, 'TAX YEAR 2025 / BILLED 2026' column). 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 Monument. 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
≈ $2,800–$3,500 / month fully financed
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 Monument Code Of Ordinances permits accessory dwelling units (§18.03.390), subject to the size, height, setback and use rules quoted above from the ordinance text. Monument is also an HB24-1152 subject jurisdiction, so since June 30, 2025 state law requires one ADU to be allowed on any lot with a single-family home. 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 Monument 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 Monument Code Of Ordinances: 600 sq ft, or 50% of the principal structure's floor area if less (standard zones); up to 1,250 sq ft in the Large Lot Residential District. Both Olerra Flex Flats — the 490 and the 735 — are designed to fit typical Colorado caps; check the rules table above for the exact ordinance text.
No — the ordinance does not permit short-term rental of an ADU here, so plan on long-term tenancy or family use.
Per the ordinance: Yes, but only as a one-time check: the owner must demonstrate residency on the parcel at the time the ADU application is submitted, not on an ongoing basis; a distinct rule applies when the ADU is built simultaneously with a new primary dwelling unit.
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 $484 per year for every $100,000 of value the ADU adds, using the local mill levy split across Colorado's TY2026 school (7.05%) and local-government (6.80%) assessment rates.
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 — Monument, CO. Data updated August 25, 2026. https://www.olerra.com/adu-calculator/monument/ <a href="https://www.olerra.com/adu-calculator/monument/">Monument ADU rules & costs</a> Data as of August 25, 2026, the oldest figure on the page.
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 September 2026. Olerra pricing: published all-in project ranges, September 2026. Corrections: sales@olerra.com.
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