ADU Rules in Eugene, OR (2026)
ADU rules, permit requirements, size limits, and fees for Eugene, OR. Source-cited from official municipal code.
Yes, ADUs are allowed in Eugene, OR.
Eugene, OR permits accessory dwelling units (ADUs) on residential properties. ADUs — also called granny flats, in-law units, backyard cottages, or secondary suites — are secondary housing units on a single-family or multifamily lot. State and local law governs the approval process. In Eugene, the local building department handles ADU permit applications. Below you will find the current size limits, setbacks, fees, and timeline for building an ADU in Eugene.
ADU Size Limits
ADU Size Limits in Eugene: Detached ADU: size varies by zoning — see official source (max height: varies — see official source). Attached ADU: size varies by zoning — see official source.
| Type | Max Size | Max Height |
|---|---|---|
| Detached ADU | See official source | See official source |
| Attached ADU | See official source | See official source |
Permit Fees
ADU Permit Fees in Eugene: Plan check fee: Varies. Building permit fee: Varies. Impact fees: None. School fees: None or N/A. Total estimated permit cost: Varies.
| Fee Type | Amount |
|---|---|
| Plan Check | $500–$2,500 |
| Building Permit | $900–$3,500 |
| Impact Fees | Eugene Metropolitan Wastewater and transportation SDCs apply — typically $5,000–$12,000 |
| School Fees | Eugene School District 4J SDCs may apply for new units |
| Total Estimate | See official source |
Permit Timeline
Eugene ADU Permit Timeline: Permit timeline has not been confirmed — contact the department for current processing times. Apply through the local building department online permit portal. Phone: (541) 682-5086.
Setback Requirements
ADU Setback Requirements in Eugene: Front setback: follows zone standard. Side setback: no minimum. Rear setback: no minimum.
Parking Requirements
Parking Requirements: Reasonable local regulations relating to siting and design does not include requirements to construct additional off-street parking for accessory dwelling units
Restrictions & Requirements
- ADU must comply with Eugene Code Title 9, Section 9.2340
- One ADU per single-family lot (additional units via HB 2001 middle housing path)
- ADU cannot be sold separately from primary dwelling
- Short-term rental of ADU (under 30 days) requires Eugene STR registration
- University Impact Area (near UO campus) may have additional housing density standards
- ADU must have permanent foundation — no RVs or mobile homes
How Many ADUs Are Allowed?
Number of ADUs Allowed in Eugene: Single-family lots: One accessory dwelling is allowed for each detached single-unit dwelling on the same lot, subject to the standards at EC 9.2750 and EC 9.2751. Multifamily properties: not confirmed — see official source.
- Single-Family Lots
- One accessory dwelling is allowed for each detached single-unit dwelling on the same lot, subject to the standards at EC 9.2750 and EC 9.2751 · Verified July 14, 2026 · Source
- Multifamily Properties
- ADUs permitted in R-2, R-3, R-4 zones per Eugene Code
Statewide Preemption
ADU Preemption
Oregon state law preempts local ADU rules — local governments cannot impose stricter standards.
View Oregon preemption detailsFrequently Asked Questions
Can I build an ADU in Eugene?
Yes. Eugene, OR allows accessory dwelling units. On a single-family lot you can build One accessory dwelling is allowed for each detached single-unit dwelling on the same lot, subject to the standards at EC 9.2750 and EC 9.2751.
How big can an ADU be in Eugene?
The maximum size for a detached ADU in Eugene is 800 square feet.
How long does it take to get an ADU permit in Eugene?
The typical ADU permit timeline in Eugene is Eugene Planning and Development processes ADU permits. Standard ADU: 4-8 weeks plan review.. Total estimated permit fees are $2,500–$7,000 permit fees plus SDCs.
Do I need extra parking for an ADU in Eugene?
Eugene parking rules for ADUs: Reasonable local regulations relating to siting and design does not include requirements to construct additional off-street parking for accessory dwelling units
Do I have to live on-site to have an ADU in Eugene?
Owner-occupancy requirement in Eugene: Reasonable local regulations relating to siting and design does not include owner-occupancy requirements of either the primary or accessory structure for accessory dwelling units
Source: Eugene Code Title 9, Section 9.2340 — Accessory Dwelling Units; Oregon Revised Statutes 197A.420. Last verified April 6, 2026. View source