ADU rules in Eugene

Table 9.2740 lists Accessory Dwelling as P(3), permitted outright, in every residential base zone (R-1, R-2, R-3 and R-4), and EC 9.2741(3) allows one accessory dwelling for each detached single-unit dwelling on the same lot. Detached units carry their own standards at EC 9.2751(17)(b): a hard-surfaced walkway at least 3 feet wide from the street or alley to the primary entrance, a covered or roofed primary entry at least 3 feet deep and wide, and 5 foot interior yard setbacks with a setback plane that slopes above 15 feet of finished grade and caps building height at 25 feet. Accessory dwellings are exempt from both minimum and maximum residential density (EC 9.2751(1)(a)1. and (1)(b)), and they are allowed on flag lots (EC 9.2775(5)(e)) and on alley access lots (EC 9.2751(18)(c)).

Eugene uses one 'accessory dwelling' use category that covers interior, attached and detached units: EC 9.0500 defines Dwelling, Accessory as 'An interior, attached or detached residential structure that is used in connection with or that is accessory to a single-unit dwelling.' EC 9.2751(17)(a) sets the attached standards, and under (a)3. a unit only counts as attached if it shares a common wall or ceiling with the primary dwelling for at least 8 feet, so a basement or internal conversion qualifies while a garage joined by a short breezeway does not. Within 60 feet of the front lot line an attached ADU takes the main building's height limit under Table 9.2750 (30 feet in R-1) with 5 foot interior setbacks; beyond 60 feet the sloping setback plane caps it at 25 feet.

The 800 sq ft / 10 percent formula in EC 9.2751(17)(a)1. governs attached and detached units alike, because EC 9.2751(17)(b) layers the detached standards on top of subsection (a). The percentage bites on small lots: a 6,000 sq ft lot allows only 600 sq ft. Square footage is measured at the exterior perimeter walls and counts hallways, entries, closets, utility rooms, stairways and bathrooms, but unheated garage or storage space attached to the unit is excluded, up to 800 sq ft under an above-garage ADU and up to 300 sq ft otherwise. In the R-1 areas inside the city-recognized Amazon Neighbors, Fairmount Neighbors and South University Neighborhood Association boundaries, EC 9.2751(17)(c)2. swaps that formula for a flat 600 sq ft cap below 9,000 sq ft of lot area and 800 sq ft at or above it, and adds bedroom caps.

Neither EC 9.2741(3) nor EC 9.2751(17) imposes any owner-occupancy condition; a full-code search on the Eugene Code platform surfaces owner occupancy only for bed and breakfast facilities (EC 9.5100). The city states it directly on its ADU program page: 'Owner occupancy of either unit is not required.' State law also forecloses the question. ORS 197A.425(1)(b)(B) provides that 'reasonable local regulations relating to siting and design' does not include owner-occupancy requirements of either the primary or accessory structure. Eugene finished aligning its ADU rules with the state mandate through Ordinance No. 20659 (adopted September 15, 2021), which resolved the Land Use Board of Appeals remands of Ordinance Nos. 20594, 20595 and 20625, so there is no void-but-still-printed owner-occupancy language left on the books.

Ordinance No. 20699, the Climate Friendly and Equitable Communities parking reform package (CA 23-1, adopted November 13, 2023, effective December 31, 2023), eliminated minimum off-street parking requirements city-wide; the adopting findings say the amendments 'will eliminate minimum off-street parking requirements City-wide.' What remains in EC 9.6410 is a maximum-parking regime: the section has subsections for parking space standards, maximum number of spaces and accessible parking only, and Table 9.6410 is captioned 'Maximum Off-Street Motor Vehicle Parking,' listing 'N/A' for Accessory Dwelling. The city's ADU program page confirms it in plain language: 'ADUs do not require additional off-street parking.' Independently, ORS 197A.425(1)(b)(B) bars Oregon cities from requiring additional off-street parking as a condition of ADU approval.

Table 9.2740 codes Accessory Dwelling as 'P' (Permitted) in R-1 through R-4, not 'S' (special development standards), 'SR' (site review) or 'C' (conditional use permit), so no discretionary land use hearing attaches. Compliance with EC 9.2751(17) is verified through the building permit, and the city's pre-approved plan program offers 13 vetted designs plus a free city plan set that skip plan review fees. The only land use application in the picture is optional: EC 9.2751(17)(d) plus EC 9.8030(34) let an applicant request an adjustment to convert an existing building that misses the ADU standards, and that route is closed inside the Amazon, Fairmount and South University boundaries. Work on a designated historic property still needs historic property alteration approval from the planning director under EC 9.8175.

Nothing in EC 9.2741(3) or EC 9.2751(17) restricts renting an accessory dwelling, and there is no minimum lease term. The 'shall not be rented as an independent dwelling' language people sometimes attribute to Eugene ADUs lives at EC 9.2751(16)(a)5. and applies to accessory buildings such as sheds and garages; EC 9.0500 states plainly that 'An accessory dwelling is not an accessory building,' so that prohibition does not reach ADUs. If the unit is used for stays under 30 days, EC 3.350(1) requires annual registration with the city (address, local contact, and whether the unit is owner-occupied), and EC 3.772(1) imposes a transient lodging tax of 4.5 percent of rent collected under EC 3.770 through 3.800. Registration is free, and EC 3.350 sets no night cap and no owner-occupancy test.