ADUs are allowed in WarrentonTypes:DetachedInternal
Types:DetachedInternal
Accessory Dwelling Unit (ADU) Rules for Warrenton, OR
Is your property eligible for an ADU?
# of Properties
3,216
Owner-occupied
64%
Zoning districts
32
Median Lot Size
0.23 acres
Avg Income
$73,207
Residential Types:
3,216 housing units
Single Family
21%
2-3 Family
6%
Apts (4+ units)
10%
Other
63%
Zoning Districts:
5,445 parcels · 32 districts
RM
21%(1,156)
R10
17%(940)
RH
13%(709)
C1
11%(598)
Other
38%(2,042)
ADU Rules
What can you build in Warrenton, OR?
Warrenton, OR follows state and local rules for Accessory Dwelling Units. Here is a concise overview of the local rules.
Eligibility
- –Internal / Attached ADU: By Right
- –Detached ADU: By Right
Interior / Attached ADU Size Limits
- –Maximum size of 600 sq ft; may increase to 800 sq ft if one additional off-street parking space is provided.
Detached ADU Size Limits
- –Maximum detached accessory dwelling unit size of 600 sq ft.
Max Units
- –1 ADU per lot; limited to lots with an established single-family residence (not authorized on duplex, triplex, quadplex, or multifamily lots).
Owner Occupancy
- –Owner-occupancy required only for the main house during homestay.
Parking
- –Min: 0 if the lot has ≥2 off-street spaces; otherwise 1 space/ADU. No citywide max; conditional max in C-1/C-MU or near transit: min×1.2 (with on-street parking) or 1.5 (without) or per parking analysis. Exceptions: no parking if ≥2 off-street spaces; director may waive/reduce; adding 1 on-site space can allow larger ADU up to 800 sq ft.
Rental Restrictions
- –Short-term rentals allowed only as part of a permitted homestay lodging and only if the main dwelling is owner-occupied.
- –ADUs may not be used as servants' quarters or lodging for housekeepers, gardeners, etc.
ADU State Law
What can you build in Oregon?
- –In urban growth areas, Oregon law requires cities and counties to allow at least one ADU on lots zoned for detached single-family homes.
- –Local jurisdictions cannot require owner occupancy for ADUs, but may regulate short-term or vacation rentals.
- –There are no statewide limits on ADU size, height, setbacks, lot size, or floor area ratio. Local zoning rules apply.
- –Parking requirements, if any, are set by the local jurisdiction, subject to state limitations.
- –Some cities may allow more than one ADU per lot, depending on local code.
- –Oregon law does not require counties to allow ADUs in rural residential zones. Whether an ADU is allowed depends on county zoning.
- –ADUs in rural residential areas cannot be used for short-term or vacation rentals.
- –Additional requirements may apply related to wildfire risk, water supply, septic capacity, and fire access.
- –Counties may impose additional restrictions beyond state law or choose not to allow ADUs at all.
- –If a county allows ADUs, state law imposes strict limits, including a minimum 2-acre lot size, a maximum ADU size of 900 sq ft, a location within 100 ft of the primary dwelling, and a limit of one ADU per parcel.
What's allowed on your lot?
These are the municipality-wide rules. What's allowed on a specific property also depends on state laws, setbacks, floor area ratio, lot coverage, environmental constraints, topography, and other property-specific factors. Search your address on FutureLot to see what's allowed on your property.
Check my propertyHow can we help you?
Get matched with trusted local builders
Understand what's allowed on your property
Learn the key rules and size limits for ADUs
Is your property eligible for an ADU?
ADU rules in other Oregon municipalities
Rules change at the town line. Check the municipality your property is actually in.
Clatsop County