Broomfield ADU rules
✓ Verified against code · August 20, 2026
Current rules under BMC §17-32-160 (Accessory Dwelling Units), adopted by Ordinance 2265, in effect since September 16, 2025. Broomfield is a consolidated city and county. Ordinance 2265, adopted September 9, 2025 and effective a week later, aligned its code with HB24-1152 and went further than the statute requires on owner-occupancy: the repeal of any residency requirement was in the ordinance from first reading and survived to adoption. Its parking test, though, is built differently from the statute's.
Common questions, answered from the code
Do I have to live on the property in Broomfield?
No, and Broomfield goes further than state law requires here. There is no residency requirement of any kind — not ongoing, and not even a check at the time you apply. The city's own FAQ says any property owner may add one ADU to any eligible property. HB24-1152 would still have permitted an application-time residency check; Broomfield chose not to keep one.
BMC §17-32-160; City ADU FAQ · Permalink
How big can a Broomfield ADU be?
Up to 500 sq ft as of right, whatever the size of your house. Above 500 sq ft the cap becomes the lesser of half your home's first-floor footprint or 800 sq ft. Garage and porch area is excluded from both calculations, so the usable living space is often larger than the raw figure suggests.
BMC §17-32-160(D) · Permalink
Do I need parking for a Broomfield ADU?
Usually not. Parking is required only where two things are both true: on-street parking is prohibited on the adjacent streets, and your ADU is not within a Parking Reduction Area. Where that happens, three off-street spaces are needed in total. Worth noting that this is a two-part test while the state statute sets a three-part one, and Broomfield substitutes its own Parking Reduction Area map for the statute's zoning test — so the two do not line up exactly.
BMC §17-32-160 · Permalink
Does a Broomfield ADU need its own water tap?
No, and this is one of the better financial breaks in the state. An ADU ties into the principal dwelling's existing water and sewer connections — no separate tap or license required, which avoids a cost that runs into the thousands elsewhere on the Front Range. If you are on septic, Broomfield Public Health has to review capacity first.
BMC §17-32-160(E), (G) · Permalink
Can I Airbnb my Broomfield ADU?
No. Short-term rentals are categorically barred in ADUs under the city's short-term rental chapter. That is a local choice the state ADU law expressly permits a jurisdiction to make.
BMC ch. 5-39 · Permalink
The rules at a glance
| ADUs allowed per lot | One per parcel — internal, attached or detached at the owner's choice, with no restriction on which type. A principal single-unit dwelling must exist or be built concurrently.BMC §17-32-160(A)–(C) |
| Maximum size | Up to 500 sq ft as of right, regardless of the principal dwelling's size. Above 500 sq ft, the cap is the lesser of 50% of the principal dwelling's first-floor footprint or 800 sq ft. Garage, porch and similar area is excluded from both calculations.BMC §17-32-160(D) |
| Detached ADU height | Set by the general accessory-building standard at BMC §17-34-030 rather than the ADU chapter. We have not been able to retrieve the figure from a primary source and will not publish a number we cannot cite.BMC §17-32-160(C)(ii), referring to §17-34-030 |
| Detached ADU setbacks | The zone's accessory-building setbacks apply, with two ADU-specific overrides: the ADU's side setback can never exceed the principal building's side setback, and the ADU cannot sit between the principal structure's front and the street. There is no alley exception — a flat five-foot standard appeared in an earlier draft and was removed before adoption.BMC §17-32-160(C)(i)–(ii) |
| Off-street parking | No new parking unless two conditions both hold: the adjacent streets prohibit on-street parking, and the ADU is not within a Parking Reduction Area. Where they do, three off-street spaces are required in total — two for the principal dwelling and one for the ADU. This is a two-part test where the statute sets a three-part one, and it substitutes a locally defined Parking Reduction Area for the statute's January 2024 zoning test.BMC §17-32-160; contrast C.R.S. 29-35-403(3) |
| Owner-occupancy | None at all — not ongoing, and not even at application. The city's own FAQ answers the question with a flat no: any property owner may add one ADU to any eligible property. This goes beyond what the statute requires, which would still permit a residency check at application.BMC §17-32-160; City ADU FAQ |
| Lot coverage / floor area | The ADU ordinance does not address lot coverage or floor-area ratio at all. General zone-district standards presumably apply as they would to any accessory structure, but we have not been able to retrieve those figures.BMC §17-32-160 (absence verified) |
| Permit path & timeline | Administrative and by-right — ADUs are permitted accessory uses in every zoning district that permits single-unit residential use, with no conditional-use or variance process. A building permit, the city's ADU checklist, and for a detached unit a recorded Declaration of Use before the certificate of occupancy. No published review timeline.BMC §17-32-160(A), (I) |
Worth knowing
- No separate water or sewer tap is required — an ADU ties into the principal dwelling's existing connections, which removes a cost that runs into the thousands in many Colorado cities. Other utilities may still be separate.
- A property on septic needs a capacity review by Broomfield Public Health.
- Short-term rentals are categorically barred in ADUs under BMC chapter 5-39 — a restriction HB24-1152 expressly allows a city to keep.
- Exterior cladding must match the principal dwelling unless a PUD, site plan or overlay says otherwise.
- Manufactured and tiny homes qualify if they are foundation-mounted and meet IRC and cladding standards; RVs, travel trailers and shipping containers do not.
- A two-occupant cap appeared in the first-reading draft and was struck before adoption — it is not in the current code.
On our watchlist
Broomfield's detached-ADU height limit sits at BMC §17-34-030 and we have not retrieved the figure — the city's code host renders section text in a way that defeated every route we tried, and no archived snapshot was found. We publish the reference without a number rather than guess one.
Lot coverage and floor-area figures are unresolved for the same reason.
Broomfield is listed as Required under HB24-1152 on the state's own subject-jurisdictions spreadsheet and does not appear on the October 2025 non-compliance reporting we could reach.
Primary sources
- Ordinance 2265 (final adopted text)
- Broomfield ADU FAQ
- Colorado DOLA — Accessory Dwelling Units (HB24-1152)
Other Colorado cities
Arvada · Aurora · Boulder · Castle Rock · Centennial · Colorado Springs · Denver · Fort Collins · Greeley · Lakewood · Longmont · Loveland · Pueblo · Thornton · Westminster
Not legal advice. Every fact above cites the code section it comes from — check the cite, or ask your city’s planning department to confirm your specific lot. Spotted an error or a new ordinance? See about to reach us; corrections are logged in the changelog.