Can I Build a Tiny House on Vacant Land in Washington?

Checking out what local zoning and safety rules say about putting a tiny house on a Washington lot.


I want to build a tiny house in the state of Washington to use as a seasonal cabin. In case I ever want to move the tiny house or sell it, I want to build it on wheels (not a permanent foundation). Is this legal in Washington? If so, will any vacant lot in the countryside work?


In Washington, the answer you are looking for may vary between local jurisdictions. What is legal in one county, may not be in another. Moreover, what is legal on one lot, may not be legal on an adjacent lot. Every case is different, so you will need to complete site-specific.

What to Find Out Before Buying Any Land

It is critical to do your due diligence and complete a thorough inspection of any property before you buy it. The objectb is to make sure your tiny house on wheels is legal. Most purchase agreements account for this by giving the prospective buyer time to complete their research (referred to as the "due diligence period").

How much time and money a buyer spends on due diligence will depend in part on the value of the land being purchased, as well as the additional importance a buyer places on being able to use the land in a specific way (such as seasonal recreational use).

In a case like yours, where you want to buy land to put a tiny house on wheels to use as a second home, due diligence should include, at a minimum:

  • a thorough review of the zoning code (see below) to confirm you can use a tiny house on the land (perhaps as a seasonal recreational vehicle),
  • a detailed examination of the building and safety standards that will apply to the construction of your tiny house on wheels to make sure it is feasible to build on your selected lot,
  • an appraisal to confirm you are paying a fair price (if you are borrowing money, the lender will require this), and
  • confirmation that the property has legal access (for instance, that you won't have to drive over someone else's property to get there), adequate domestic water, no boundary line issues, and clear title.

Performing additional due diligence may be prudent, such as a building inspection if there is an existing structure or an environmental assessment. An experienced Washington state real estate agent can be a valuable resource in a situation like this. Not only can the agent help locate potential properties, but he or she can advise you on due diligence issues, and when necessary, refer you to local experts, such as surveyors, builders, and attorneys.

The Applicable Zoning Code Controls Development

In Washington, under the Growth Management Act (GMA), cities and counties adopt zoning and development regulations. Zoning regulations control how land can be used and developed.

In the case of rural land, the GMA distinguishes between natural resource lands (agricultural, forest, and mineral resource lands) and non-resource lands (such as rural residential). This distinction may be important when looking at land to put your tiny house on, since resource land is more tightly regulated to ensure that it remains available for resource use. Depending on how you plan to use the land and how large a tract you want to buy, non-resource land (such as a rural residential zone) may be easier to develop than resource land.

As you review the zoning code and map, look for:

• what the underlying zone is (for example, residential or agricultural)

• what uses are allowed in that zone (for example, look to see if RVs are a legal use) and whether your will need to apply for a permit

• what development standards apply, such as minimum lot sizes, setbacks, and even minimum home size, and

• what building standards apply.

In Washington, like in other states, you will likely find that your tiny house on wheels falls into a gray area of the law. Where the use is only for part of the year, for example, perhaps it will qualify as “camping” or a similar recreational use. In some counties, a tiny house on wheels may meet the definition of an RV and be lawful in some zones. In Snohomish County, for instance, if your tiny house meets the definition of a “recreational vehicle,” you might be able to leave it on your property for 180 days in some zones. Note, though, that in Snohomish county you would likely have to remove the trailer for the other half of the year.

If you do not understand the applicable zoning code, it is important to talk to the local planning department or your attorney. Before you spend money on buying a lot for your tiny house, make sure your tiny house will be legal. It would be a big disappointment to buy some land, to find out you cannot use it how you want to.

Your Tiny House Must Meet Washington Safety Standards

Like a tiny house on a foundation that must comply with the local building code, tiny houses on wheels have to be built to certain safety standards. Since a tiny house on wheels more or less meets the definition of a recreational park trailer, state law likely requires it to be built to comply with American National Safety Institute (“ANSI”) standard 119A.5.

If you plan to buy a tiny house on wheels, the manufacturer should attach an insignia that certifies it meets the required safety standards. You may also have to comply with building and safety standards if you build the tiny house yourself. Before buying or beginning construction, confirm with the local jurisdiction what certification requirements apply.

Ignoring Washington Zoning Codes and Building Standards Is a Risk

It may be tempting to think that you are just bringing a tiny house on wheels out to the country and that no one will care, so it is not worth spending the time and money on the necessary permits. That may very well be the case, however, failing to get the necessary permits is taking a significant risk. If someone turns you into code enforcement, you may have to pay a fine and move your tiny house.

A Washington land-use attorney can help you identify all applicable laws and determine whether your tiny house will be lawful. Since tiny houses are a relatively new issue for planners to deal with, you may encounter hesitation or obstructions to your tiny house. If so, you may want to talk to your lawyer about whether it is possible (and cost-effective) to amend the local zoning laws to allow your tiny house.

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