About tiny homes

A tiny home is a dwelling that may be built on wheels and is no larger than 400 square feet, including a kitchen, bathroom, and sleeping/living area, and must be built to the Washington State Building Code. The approval process for a tiny home depends on where it's built.

On this page, you can determine whether you need approval of construction plans and inspections from L&I or the local building department where the home is being built.

  • If you're building a tiny home somewhere OTHER than where it will be occupied and used, then see the Building a Tiny Home tab.

Next, see the Building a Tiny Home tab.

Building a tiny home

L&I is the building department for the construction of tiny homes that are built at offsite locations, such as a factory or even a back yard. L&I reviews plans and inspections for tiny homes built offsite from where they will be placed.

NOTE: The design of your tiny home must also meet local building department criteria. Contact your local building department for their requirements and permit information.

To get a tiny home approved:

First, Download and review the tiny home information packet. It includes the standards to which you need to design, plan, and build your tiny home.

We will need 3 copies of your plans. Plans must be stamped by a Washington professional engineer (PE) or architect.

Next, fill out these applications:

  • Tiny Home Plan Approval & Insignia Request form (F623-039-000): This is your basic application and gets the insignia for the L&I inspector to place on your tiny home. This also gets the insignia for the L&I inspector to place The insignia is also important when talking with your local building department when you place the residence.

  • Notification to Local Enforcement Agency (F623-013-000): This is included with a copy of your plan that is sent to the local building department upon L&I approval.

Finally, include payment of $745.10 for plan review and insignia. We will notify you if we need more information or when your plans are approved.

Mail the completed packet to:

Department of Labor & Industries
Factory Assembled Structures
P.O. Box 44430
Olympia WA 98504-4430

You can also submit your plans at your local L&I office, and pay the fee by cash, check, money order, or credit/debit card.

Because of the large number of requests, it can take several months for L&I to review plans. We will notify you if we need more information or if your plans have been approved.

Next, see the Do the Work tab.

Do the work

Once plans for your tiny home are approved, you can start work.

Some important notes about licensing requirements:

When you build a tiny home there are several registration, and licensing issues you need to be aware of and consider.

  • You may need to be a registered general contractor depending where you are going to work on a tiny home, and what duties you are performing. Contact L&I's contractors program to find out the requirements for your situation.
  • All plumbing must be installed by a Washington state licensed residential or commercial plumber.
  • All electrical work must be performed by a Washington State licensed electrical contractor and licensed electricians. You will need to get an L&I electrical permit to connect your home to power.

There are exceptions for homeowners doing electrical and plumbing work on their own home. Please contact L&I's plumbing program and electrical program to determine the licensing requirements for your situation.

Note: Local building permits will be required for everything from the tiny home's foundation, installation, and its location on a property. Remember to contact your local building official for more information.

Next, see the Get Inspected tab.

Get inspected

You will need to have your tiny home inspected several times by L&I as you complete certain stages of construction. You must contact us using either an in-state or out-of-state inspection request form before covering any work on the home. Our inspector will contact you to confirm an appointment.

When you need an inspection depends on when you complete the stages of construction shown on the form. This can include:

  • Floor
  • Plumbing
  • Electrical
  • Frame
  • Mechanical
  • Energy Code
  • Final

Be ready for the inspection. If you've requested an inspection and you're not ready, you will still be charged. If the inspector must return to the location, you will be charged additional fees.

Related Resources

Contact Us

  • FAS1@Lni.wa.gov
  • 1-800-705-1411 Option 3

Mailing address

Washington State Department of Labor & Industries
Factory Assembled Structures
PO Box 44430
Olympia WA 98504-4430


7273 Linderson Way SW
Tumwater WA 98501