Everything homeowners ask about building an ADU in Beaverton — answered with 2026 data.
Yes, ADUs are allowed in Permitted (P) in all four residential zones, MR, RMA, RMB and RMC (Table 20.05.20.A, row 2.A), on a lot whose principal use is a single-detached dwelling (40.05.10; 60.50.03.2.A). In MR only an existing house (as of June 30, 2022) qualifies, since new single-detached dwellings are prohibited there. ADUs also appear in the commercial (20.10.20), multiple-use (20.22.20) and downtown (70.15.20) use tables; check the row for your zone. in Beaverton, OR. The maximum size for a detached ADU is 800 sq ft of floor area (60.50.03.2.C.1). No percentage-of-house rule. A detached ADU can be a new building or a manufactured home (60.50.03.2.B.3). An ADU added to a house that existed on June 30, 2022 is excluded from the zone's floor-area-ratio cap (60.50.03.2.C.4); an ADU built with a new house counts toward FAR (1.40 RMA, 0.80 RMB, 0.60 RMC for single-detached, Table 20.05.15.H.1). Attached ADUs can be up to 800 sq ft of floor area. Beaverton has an ADU-friendliness score of 8/10. Check our full Beaverton ADU rules page for complete zoning details.
ADU construction in Beaverton typically costs $165,000-$300,000. The cost per square foot averages $200-$420. Garage conversions are more affordable at $70,000-$160,000, while prefab ADUs cost $100,000-$240,000. Permit fees add The ADU land-use fee is set in the Citywide Comprehensive Fee Schedule (Exhibit A to the fee resolution) and the building permit is valuation-based (Building Permit Fee Schedule B70-1108); both PDFs were behind a bot check on 9/20/2026, so confirm current figures with Community Development. to your budget. See our detailed Beaverton ADU cost guide.
Detached ADUs in Beaverton can be up to 800 sq ft of floor area. Attached ADUs are limited to 800 sq ft of floor area. Junior ADUs (JADUs) have a cap of N/A: Oregon and Beaverton have no junior-ADU category. A conversion inside the house is simply an ADU under 60.50.03; if a second unit fits both the ADU and the duplex definition the owner chooses which to apply for (Ch. 90, Dwelling Types). Maximum height is The zone height limit applies: 40 ft in RMA, 35 ft in RMB and RMC (Table 20.05.15.G.1; RMB/RMC also subject to the 20.30 height limits); MR uses the height-transition standards of 60.05.15.7. To use the 5 ft rear-setback option the ADU must be one story and no more than 15 ft above finished grade (60.50.03.2.E.2). You are allowed up to One ADU per single-detached dwelling on a qualifying lot.
Rear setback: 15 ft in RMA, RMB and RMC (Table 20.05.15.F.3), reduced to 5 ft for a one-story ADU no taller than 15 ft measured from finished grade (60.50.03.2.E.2). No ADU may be placed over any easement (60.50.03.2.E.3). Side setback: Table 20.05.15.F.2 (as amended by ORD 4879, Apr 2026) lists 5 ft from a perimeter lot line and 3 ft from internal lot lines created by a land division; a detached ADU must also keep 6 ft from the house and other buildings on the lot (60.50.03.2.E.1; Table 20.05.15.F.6). Confirm the side yard for your lot with the Planning Division. Front setback: 10 ft minimum front yard in all residential zones (Table 20.05.15.F.1.a); a garage face must be at least 18.5 ft back in RMB and RMC (F.4.b). ADUs are normally placed behind the house, so the rear and side rules govern. Note that garage conversions may be exempt from setback requirements if the existing structure is already within the setback area.
None. Beaverton removed minimum parking for every use in August 2023 (Development Code 60.30.10, ORD 4844), and ORS 197A.425(1)(b)(B) separately bars cities from requiring extra off-street parking for an ADU. Any spaces you do build must be 8.5 ft by 18.5 ft; up to two may sit in the front yard (60.30.10). Many cities and states have been relaxing ADU parking requirements in recent years. In California, no additional parking is required for ADUs near transit.
Not required. Section 60.50.03 contains no owner-occupancy rule and ORS 197A.425(1)(b)(B) (formerly ORS 197.312(5)) prohibits cities from imposing one; the state exception lets cities restrict short-term rental of ADUs, so ask the city before listing the unit for stays under 30 days. Note that owner-occupancy rules vary by state law — California and several other states have eliminated this requirement for standard ADUs.
The ADU permit review timeline in Beaverton is typically Not published. The Type 1 ADU decision is made by the Director without a hearing (40.05.15.1.B; procedure in 50.35), then building plan review follows; confirm current turnaround times with Beaverton Planning and Building before scheduling a contractor. Plan check: Structural, energy, fire-separation and plumbing plan review is part of the building permit (Building Division); the land-use decision under 40.05.15 checks zoning only. Detached ADUs must be 6 ft from other buildings or meet the Residential Specialty Code's fire-separation rules. Pre-approved plans availability: No Beaverton pre-approved ADU plan program was found on the city's site or in the Development Code as of Sept 2026; confirm with the Planning Division before assuming one exists.
Average ADU rental income in Beaverton: 1-bedroom units rent for $1,400-$1,650/month, 2-bedroom units for $1,600-$1,900/month. Short-term rentals: Not verified. Expected ROI: 5-8% gross rental yield on a $165,000-$300,000 build at $1,400-$1,900/mo (estimate before taxes, vacancy and financing).
The minimum lot size for an ADU in Beaverton is No ADU-specific minimum lot size (60.50.03 sets none). The minimum lot areas in Table 20.05.15.B (1,500 sq ft RMA, 3,000 RMB, 5,000 RMC for a single-detached lot) apply to land divisions and middle housing, not to adding an ADU to an existing lot (footnote 2). The application must be filed by the owner or the owner's agent (40.05.15.1.D). This applies to detached ADUs — garage conversions and JADUs may have different or no lot size requirements.
Garage conversions are one of the most popular and affordable ADU options. In Beaverton, a garage conversion typically costs $70,000-$160,000. The key advantages are lower cost (no foundation work), potential setback exemptions, and faster permitting. Read our complete garage conversion guide.
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