Tiny Home on Foundation as ADU

Boise (City), Idaho


Name Tiny Home on Foundation as ADU
Municipality Boise (City)
Zoning Districts Most Residential Zone Districts
Effective Date 02/09/2021
Municipal Code 11-06-03: RESIDENTIAL USE STANDARDS: 1. A.
Code Link https://codelibrary.amlegal.com/codes/boiseid/latest/boise_id/0-0-0-32206
Authority Planning and Development Services


Accessory Dwelling Unit (ADU)

What is an Accessory Dwelling Unit?

Accessory Dwelling Units (ADUs) are a second, smaller dwelling that can be built on a property already occupied by a single-family home. They are often called “mother-in-law suites”. The intent is to provide more affordable housing and increase density while maintaining the single-family dwelling character of the property. Boise City Code for ADUs can be found online at citycode.cityofboise.org under Section 11-06-03.1(A). ADUs in the Historic District require a Certificate of Appropriateness prior to submittal of an ADU application.

ADUs are not “tiny homes on wheels,” as these mobile dwellings are considered recreational vehicles or campers by the city’s development code. Such tiny homes are prohibited from being classified as ADUs by the city’s development code. Additionally, due to the mobile nature of tiny homes on wheels, they pose additional regulation challenges in terms of building safety, life safety, and relevant area design standards.


  • No larger than 700 square feet or 10% of the lot size, whichever is smaller
  • Ongoing owner occupancy of either the primary residence or the ADU is required, enforced by a deed restriction
  • No more than 2 bedrooms
  • Two-bedroom ADUs must provide one additional dedicated parking space on site in addition to the two required parking spaces for the single-family dwelling outside of setbacks per zone.
  • Impact fees for accessory dwelling units shall be assessed at a portion of the standard single family residential fee as determined by the applicable agency
  • Notification of the adjacent property owners and occupants, including properties across streets and alleys, must be submitted with the application
  • The application and submittal requirements checklist can be found above

Key Contacts

Planning and Development Services
Boise City Hall
150 N. Capitol Blvd. – 2nd Floor
Boise, ID 83702
Phone: (208) 608-7100


Source: City of Boise Planning and Development Services

ADU Handout

Updated:  October 2023 – Laura

THIA will be constantly updating the legislation data. Check back often. Suggest A Correction if you are aware of any missing or incorrect information. AND keep scrolling to learn more about getting guidance.



Building Code — Legislation that speaks to how to construct a tiny house.

Zoning Code — Legislation that speaks to how the lot will be used.


ADU — Accessory Dwelling Unit

DMV — Division of Motor Vehicles

IB — Industrialized Buildings

IRC — International Residential Code

PUD — Planned Unit Development

RV — Recreational Vehicle

SF — Single Family Dwelling

T — Transitional Housing

UDO — Unified Development Ordinance

Please Suggest a Correction if you find broken links or misinformation.

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