Colorado ADU compliance scorecard
✓ Verified against code · August 20, 2026
Colorado’s ADU law required every city of 1,000+ residents inside a metropolitan planning organization to allow one ADU wherever a single-family home is allowed — administratively, without owner-occupancy mandates, without most parking mandates — by June 30, 2025. Fourteen months later, adoption across the Front Range ranges from generous early compliance to open defiance. Every status below is verified against codified code or adopted ordinance text and independently fact-checked; where a city’s code conflicts with the statute, state law controls — but the permit counter applies the city’s code until it’s amended.
| City | Status | The specifics |
|---|---|---|
| Aurora | Non-compliant (state-listed) | No compliance ordinance exists — council voted one down 6–2 (June 2025). Codified rules remain detached-only, 650 sq ft, owner-occupancy, conditional-use hearings, Original Aurora subdistricts only. State formally listed Aurora as non-complying (Oct 2025); a corrective ordinance was in staff drafting as of July 2026. |
| Thornton | Non-compliant (state-listed) | The September 2025 reenacted code kept ongoing owner-occupancy enforced by a recorded deed restriction — barred by C.R.S. 29-35-403(2)(b) since June 30, 2025. Otherwise statute-shaped. State-listed non-complying (Oct 2025); no fix found through Aug 2026. |
| Arvada | Non-compliant (state-listed) | August 2025 code amendment (after the deadline) retained ongoing owner-occupancy with CO-linked deed restriction, a blanket 1-space parking mandate, and a 600 sq ft cap on small lots — inside the statute’s protected 500–750 range. State-listed non-complying (Oct 2025). |
| Greeley | Apparent conflicts | ADU section unamended since Feb 2023: ADUs not allowed in R-E/R-L/H-A though houses are; 1-space-per-bedroom parking; a 60%-of-home size formula that can block protected sizes. Yet the state’s Oct 2025 review did not list Greeley — a genuine puzzle. Statute controls over conflicting code. |
| Colorado Springs | Compliant — stricter by design | Adopted on time (April 2025), but council cut detached height to 16 ft on the floor, restored a 1-space parking mandate staff proposed eliminating, and wrote home-rule authority to supersede conflicting state law into the recitals. A preemption dispute waiting for a test case. |
| Pueblo | Compliant (late, state extension) | New ADUs were prohibited citywide until August 25, 2025 — but Pueblo held a six-month state extension, then adopted near-verbatim statute language. Distinctive: a 7-of-17 design-feature menu for detached units. |
| Lakewood | Compliant — repeal-restored code | Voters repealed the entire fall-2025 zoning rewrite (April 7, 2026, ~62.5%) after it was law for twelve days. The restored pre-rewrite code — amended June 2024 for state compliance — governs: 1,400 sq ft ADUs, permit-time-only owner check. Re-adoption barred until ~Oct 2026. |
| Denver | Compliant | Citywide ADUs by right since Dec 2024 (ending parcel rezonings); all vehicle parking minimums repealed Aug 2025; application-time owner check only — the statute’s exact carve-out. PUDs forced to allow ADUs by a Feb 2026 amendment. |
| Westminster | Compliant | Complied six months early (Jan 1, 2025) with statute-shaped rules, then codified the 750 sq ft small-home guarantee in March 2026 at the state’s insistence — the compliance-review process visibly working. Publishes a 4-week review timeline. No impact fees. |
| Boulder | Compliant | Two-stage unwind of the state’s most restrictive legacy regime: saturation caps died Sept 2023, owner-occupancy March 2025. Size caps remain the region’s tightest (800 sq ft detached; 1,000 with an affordable-rent restriction). |
| Longmont | Compliant | June 2025 rewrite tracks the statute, with local flavor: proof of city residency at application (a broader reading than the statute’s on-parcel check), a total STR ban on ADUs, and a floodplain prohibition. |
| Fort Collins | Compliant | ADUs in every zone district via staff-level review since Feb 2025, no parking, no owner-occupancy. The catch is cost: a $6,925 flat review fee and $20,000–25,000 typical total fees before construction. |
Sources: each city page carries the full ordinance citations and primary-source links. The state’s non-compliance determinations are from Colorado DOLA’s October 2025 quarterly compliance review. This scorecard updates as cities amend — every change lands in the changelog. Not legal advice.