Is a Tiny Home Legal in Clark County or Multnomah County?

Updated 2026: This article was written in 2019. Washington’s HB 1337 (2023) and Oregon’s statewide ADU rules have since expanded where ADUs are allowed inside urban growth areas. The permit categories below still apply, but check the current rules in our Clark County ADU guide, Washington ADU laws guide, and Oregon ADU rules guide before you plan a project.

Is it legal to own a tiny home in Clark County or Multnomah County? We’ve been asked this question hundreds of times over the years, and the answer never fails to surprise.

Let’s start with the framing of the question: owning a tiny home and inhabiting a tiny home are two very different things. Just as you might own an RV or camper trailer and leave it on your property, living in the unit means a completely different set of criteria must be met.

For the sake of this post, we’ll assume you’re interested in both owning and occupying or renting your tiny home.

So is it legal? The short answer is it depends on the jurisdiction your home will be located in, and on what standards your home was built to.

Different types of permittable structures

While permitting isn’t required to own a tiny home, it is necessary in most cases to inhabit the home long term. Most counties and cities in the Pacific Northwest will only permit a structure that has been placed on a foundation.

Homeowners who prefer to keep their home trailer-mounted instead will face rules and regulations similar to those for an RV, meaning that often you will be limited to short-term occupancy and will be unable to offer the unit for rent.

Each jurisdiction allows certain structures to be added to a parcel, though the naming conventions vary. For example, an accessory dwelling unit might instead be referred to as a secondary dwelling unit in the City of Hillsboro.

Here are the main ways a home might be permitted.

Primary dwelling

A primary dwelling is considered the only habitable structure on the property. It’s common for most jurisdictions to allow a tiny home as a primary dwelling, but more often than not you will need to first meet community requirements.

Most subdivisions or properties that fall within a homeowners association’s boundaries are subject to more specific rules, such as a minimum home size. This is typically done in an effort to control neighboring property values.

Some areas offer an alternative specifically for small homes, such as cottage housing.

Accessory dwelling unit

The most common permit issued to a tiny home is for use as an accessory dwelling unit, also known as an ADU. While a primary dwelling is the only structure on a parcel, an accessory dwelling unit is not.

A home is classified as an accessory dwelling unit if it contains bedrooms and is allowed to utilize a range for cooking, both fundamental needs in a “dwelling.”

It is important to understand that a bedroom is differentiated by the inclusion of closet space. A room that does not contain a closet may instead be referred to as an office.

Accessory structure

Not to be confused with an accessory dwelling unit, an accessory structure does not need to meet the criteria of a “dwelling.”

This means that while it is an additional structure to the primary dwelling on the property, it does not need to feature a bedroom, nor is it allowed to include a range.

Though less common than an ADU, many counties have adopted accessory structures among their permitted structure types.

Guest house

A structure classified as a guest house is similar to an accessory dwelling unit because it also includes bedrooms.

Where the two structures differ is their use of a stove. An ADU may include a range, while a guest house may not. This is commonly worked around when needed with the use of an electric cooktop.

It is common in rural areas for the jurisdiction to allow a guest house but not an accessory dwelling unit.

Hardship

While the rules and regulations may make it difficult to complete your project in some areas, a common alternative is the use of a hardship affidavit.

Many jurisdictions will allow flexibility in their rules if it helps to ease the financial or medical burden of a family member. This can include housing for someone with a disability, financial hardship, or simply old age.

Rural areas often offer a hardship as a means to add an ADU.

Comparing urban and rural requirements

While any address in the United States will inherently fall within a county, not all fall within city limits. The difference dictates whose requirements you must meet: the county’s or the city’s.

Though typically each is different, you are also more likely to run into additional community regulations if you are located within the municipal boundaries of a city, such as a homeowners association’s CC&Rs. See Can your HOA (homeowners association) stop you from building an ADU in Washington?

Clark County

For those located in Clark County, Washington but not within a city jurisdiction, you are somewhat limited.

Tiny homes may be permitted as a primary dwelling or a guest house. Additionally, Clark County supplies a hardship affidavit for circumstantial permits.

While we offer permitting services with our modular homes, those who wish to go through the application process themselves can learn more in our Clark County ADU rules guide.

Property owners may instead find themselves within a city’s jurisdiction. You can find more on the following municipalities in Clark County:

• The City of Vancouver
• The City of Battle Ground
• The City of Woodland
• The City of Camas
• The City of Washougal

It is important to note that if you successfully complete a hardship permit, you will need to renew your application annually via mail or a visit to the county’s permitting office.

Multnomah County

If you’re located in Multnomah County, you have many more options in how your tiny home is permitted, thanks in part to the Residential Infill Project.

Depending on whether you are located within city limits or not, you will either report to Multnomah County directly or to the City of Portland.

The difference of jurisdiction changes what types of homes are allowed on your property as well as other zoning and setback requirements. Structures allowed in Multnomah County include an accessory dwelling unit, an accessory structure, a guest house, and a hardship.

You can learn more about ADUs in Portland and our Portland service area.

What happens if you don’t apply for a permit?

To answer the original question: yes, it’s legal to live in a tiny home in Clark County or Multnomah County as long as you get a permit, or the regulators announce that they won’t be enforcing the rules, as happened in Multnomah County and Portland, OR.

If you still have questions about the technical details of a specific site being legal for a tiny modular home, please don’t hesitate to reach out to us or start with a free property evaluation, and we’ll do our best to answer any questions you might have.