Zoning & Permits
Although zoning laws in the Northwest vary depending on whether a tiny home is on wheels (THOW) or on a permanent foundation, tiny homes are an incredibly flexible housing solution, with options to suit a wide range of lifestyles, property types, and living needs. Tiny homes, also known as Park Model RVs, are built to ANSI 119.5 standards, which fall under a special category that keeps the process simple and satisfies ADU requirements in some Oregon counties. Unlike traditional homes, they don’t require full building permits—just a level space, utility hookups, and compliance with local zoning. Below is a breakdown of the key differences, regulations, and where each type can be legally placed.
Tiny Homes on Wheels (THOWs)
Keeping your tiny home on the chassis and wheels classifies it as a recreational vehicle (RV). Tiny homes are typically allowed in communities like tiny home villages and RV parks, as well as on residential lots if they meet local requirements. However, most areas do not allow a THOW as a standalone permanent home on a standard residential lot.
📍City Example: Portland
Portland allows THOWs, provided they comply with utility hookup standards.
Tiny Homes on a Permanent Foundation
A tiny home on a foundation is considered a legal dwelling unit. It can be placed on a residential lot as a primary dwelling or ADU if it meets local zoning, utility, and minimum lot size requirements, as well as within a tiny home community. Tiny homes may also be allowed on rural land in some counties if they satisfy minimum square footage, septic permits, and land use approval.
📍City Example: Eugene & Bend
Both cities allow tiny homes as ADUs and are exploring zoning changes to permit standalone tiny home developments.
Zoning Information by Area
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Portland, Oregon – one of the easiest places in America to place a Park Model RV Tiny Home
Why Portland is great for park-model tiny homes
One tiny home on wheels is welcome on any residential lot that already has a house, attached house, or manufactured home
No building permit required. Because the city classifies an inhabited THOW or park-model RV as an “occupied recreational vehicle,” it is treated like a vehicle rather than a building. You simply register the unit with the DMV and connect it to power, water, and sewer through standard RV-style hookups
Fast set-up and minimal red tape. Typically, the only permits needed are a basic electrical outlet permit and a plumbing permit for the sewer connection .
Long-term living is allowed. You or a tenant may live in the unit full-time (month-to-month or longer). Short-term rentals such as Airbnb are not permitted .
Keep the wheels on. The home must remain mobile and parked behind the front façade of the main house. It cannot be placed on a vacant lot .
Room for two permanent ADUs as well. If you want additional space, Portland’s zoning generally allows up to two code-built ADUs on the same lot. A tiny home on wheels can occupy one of those ADU “slots” (“replacement ADU” option) .
What doesn’t apply
The city’s System Development Charge (SDC) Waiver Program only applies to ADUs that are built to residential building code on a permanent foundation. Park-model RVs and THOWs do not pay SDCs, but they also do not receive the waiver.
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Unfortunately, our tiny homes are not currently allowed to be placed as ADUs in Gresham.
Helpful resources:
Contact:
Urban Design and Planning
Phone: 503-618-2831
PlanningTech@GreshamOregon.gov
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✓ Tiny homes allowed as ADUs
✗ Tiny homes on wheels not allowed as ADUs
ADUs are permitted within the City of Troutdale as long as they are placed on a foundation; THOWs are not permitted as ADUs, but they can be used as a primary residence when they are placed in an RV or manufactured home park. The City of Troutdale allows ADUs to be used as long- or short-term rentals as long as the owner has the proper business license.
Helpful resources:Troutdale Municipal Code
Contact:
Planning
503-674-7272
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✓ Tiny homes allowed as ADUs
✗ Tiny homes on wheels not allowed as ADUs
ADUs are permitted in all residential zones, subdistricts, and overlays that permit single-family detached dwellings. Owner occupation of either the primary residence or ADU is required or the owner may appoint a family member as a resident caretaker of the principal house or ADU.
Helpful resources:
Contact:
Sarah Selden, Community Development Director
503-674-6242
Alex Lopez, Associate Planner
503-674-6232
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✓ Tiny homes allowed as ADUs
ADUs are permitted in single family zones, and in the single family areas of the Town Center Zone. No ADU in part or in total may be used as a short-term vacation rental unless it or the principal unit is owner-occupied. The ADU shall comply with the setback and dimensional requirements of the underlying zone. The ADU shall be designed so that, to the degree reasonably feasible, the appearance of the building conforms to the original design characteristics and style of the primary building.
Helpful resources:
Section 395 Accessory Dwelling Units
Contact:
Mary Dong
Building Permits & Code Enforcement
MaryD@WoodVillageOR.gov
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✓ Tiny homes on wheels typically allowed outside the Urban Growth Boundary (UGB)
Tiny homes can sometimes be placed as an ADU as long as they are a permitted dwelling—NW Tiny Homes models satisfy this requirement to be “stick built,” manufactured, or prefabricated. The ADU may not be a tiny home on wheels. There are rules and regulations for placing a tiny home as an ADU depending on if you’re inside urban growth boundaries and unincorporated communities or not.
City of Milwaukie: Please note that structures with wheels are considered a vehicle and cannot be lived in per code. Wheels will need to be removed from tiny houses for occupancy. Since tiny houses are another dwelling unit on a property, make sure your property is zoned for another dwelling. To check zoning requirements with the planning department, please email planning@milwaukieoregon.gov.
Helpful resources:
ADUs and RVs as options for secondary dwellings
Contact:
Clackamas County Planning and Zoning
503-742-4500
zoninginfo@clackamas.us
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✓ Tiny homes allowed as ADUs
✗ Tiny homes on wheels not allowed as ADUs (but may qualify as a cottage in a cottage configuration)
Tiny homes on foundations qualify as an ADU to a single-family dwelling. ADUs cannot be used for short-term rentals; however, they are permitted for long-term rentals (30 days or longer). THOWs are not allowed. Additionally, tiny homes may qualify as a cottage in a cottage configuration under Hood River’s Middle Housing Ordinance so long as they meet the standards for 17.25.
Helpful resources:
Ch. 17.25 Middle Housing Development Standards
Ch. 17.23 Accessory Dwelling Units (ADUs)
Contact:
541-387-6840
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✓ Tiny homes allowed as ADUs
✗ Tiny homes on wheels not allowed as ADUs
A tiny house on a foundation is generally allowed in unincorporated Washington County wherever a dwelling is permitted as either a primary dwelling or an ADU. A tiny home on wheels is prohibited in urban unincorporated Washington County for use as a dwelling unit. However, aTHOW may be permitted as a temporary health hardship dwelling in the rural area under qualifying conditions. If permitted through the health hardship application process, the use includes one temporary living accommodation, for a period not to exceed two years.
Helpful resources:
Contact:
lutdir@washingtoncountyor.gov
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✓ Tiny homes allowed as ADUs
✗ Tiny homes on wheels not allowed as ADUs
One ADU is allowed in conjunction with a detached single-family dwelling on a lot zoned for single-family development within an Urban Growth Boundary (UGB) of a city. Recreational vehicles are not allowed as an ADU, meaning you’d need to place your tiny home on a permanent foundation rather than leaving it as a THOW.
Helpful resources:
Contact:
503-397-1501
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✓ Tiny homes allowed as ADUs
✗ Tiny homes on wheels not allowed as ADUs
A maximum of one ADU is permitted per principal single-family dwelling on land zoned for rural residential use. Recreational vehicles are not allowed as an ADU, meaning you’d need to place your tiny home on a permanent foundation rather than leaving it as a THOW. Provisions vary depending on if the land is located within or outside an Urban Growth Boundary (UGB).
Helpful resources:
Zoning Ordinance Section 1014 Accessory Dwelling Units
Contact:
Yamhill County Planning and Development
503-434-7516
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✓ Tiny homes allowed as ADUs
✗ Tiny homes on wheels not allowed as ADUs
One ADU may be sited on a lawfully established property located in unincorporated community residential zoning districts. An ADU must be set on a permanent foundation; THOW are not permitted. There is no minimum land area requirement for an ADU.
Unincorporated community of Netarts: In the NT-RMD zone, the following uses and their accessory uses are permitted outright, subject to all applicable supplementary regulations contained in this ordinance: one or two dwelling units (attached or detached); manufactured home; the use of recreation vehicles (including THOW) is permitted outright in Wilson Beach provided that the standards of Section 5.160 and all other applicable development standards are met.
Helpful resources:
Article 5.110 Accessory Dwelling Unit (ADU) Standards
Article 5 Special Use Standards and Exceptions
Netarts Residential Manufactured Dwelling Zone (NT-RMD)
Contact:
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✓ Tiny homes allowed as ADUs
✗ Tiny homes on wheels not allowed as ADUs
In urban zones, up to two ADUs can be established on a lot with one single-family residence. A Certificate of Occupancy must be issued by the Clark County Building Safety program. Cottage configurations are allowed.
Helpful resources:
Contact:
Developing Your Property
Once you’ve confirmed that your land meets the zoning requirements, consider the following steps to prepare your land:
Zoning Compliance: Confirm that no restrictions prevent placing a tiny home on your land. A title search or consultation with local zoning authorities can provide clarity.
Access: Ensure that your site is accessible for delivering your tiny home. Roads should be wide enough to accommodate large delivery trucks.
Utilities: Verify that utilities like water, sewer, and electricity are accessible on your property.
Permits: You will need building permits and potentially additional permits for utility connections.
At NW Tiny Homes, we can connect you with professionals to help navigate these requirements and prepare your property for your Park Model RV Tiny Home.
Disclaimer: While we do our best to keep this information up-to-date, it is intended only as a general overview. Zoning regulations and requirements can vary significantly between jurisdictions and change over time, so it’s crucial to always consult your local zoning board to verify current rules and regulations specific to your property.