Loveland, CO Accessory Structures: ADU Rules (2026)

Colorado House Bill 24-1152 (signed by Governor Polis May 2024, effective June 30, 2025; codified at CRS 29-32-101 et seq.) requires 'Subject Jurisdictions' along the Front Range and I-25 corridor - including the City of Loveland - to allow at least one accessory dwelling unit (ADU) as an accessory use to every single-unit detached dwelling on a residential lot, subject to administrative approval only. The law preempts local regulations that: require a public hearing for ADU approval; impose owner-occupancy requirements; require off-street parking for the ADU (in most circumstances); require ADUs to match the principal dwelling's architectural style through subjective design review; or impose discretionary or 'subjective' design standards. Loveland updated UDC Title 18 to comply on or before the June 30, 2025 deadline and was certified by the State of Colorado as an 'Accessory Dwelling Unit Supportive Jurisdiction' in February 2026. Under Loveland's adopted UDC rules: (1) one ADU per single-family lot; (2) ADUs are allowed wherever a single-family dwelling is allowed (single-family residential zones only - not on duplex, townhouse, or multifamily lots); (3) maximum size is 75% of the primary dwelling's floor area, or - whichever is smaller - 900 sq ft (lots up to 15,000 sq ft), 1,000 sq ft (lots 15,000-100,000 sq ft), or 1,200 sq ft (lots over 100,000 sq ft); (4) ADUs may be attached (basement conversions, additions, in-law suites within the principal dwelling) or detached (backyard cottage, garage conversion, new detached structure); (5) detached ADUs are subject to the underlying accessory-structure setback requirements - typically 5 ft from side and rear property lines, and may be set back as little as 5 ft from a rear property line abutting an alley; (6) ADU height cannot exceed the principal dwelling; (7) ADUs are excluded from the residential density calculation in UDC Section 18.03.02 (do not count toward maximum density); (8) capital expansion fees are waived for ADUs as an affordability incentive; (9) administrative approval only - no public hearing, no neighborhood approval, no subjective design review; (10) owner-occupancy is not required (HB 24-1152 preempts); (11) off-street parking is not required in most circumstances (HB 24-1152 preempts). Mobile homes and RVs cannot serve as ADUs. The ADU must include independent living facilities (kitchen, bathroom, sleeping area). Loveland's Development Services / Current Planning Division processes ADU applications administratively from 410 E. 5th Street (970-962-2523), with the Building Division (970-962-2727) issuing building permits for construction.