Movable Tiny House as ADU

Humboldt (County), California


Name Movable Tiny House as ADU
Municipality Humboldt (County)
Zoning Districts Residential Single-Family Zones Inland areas only; MTH are not allowed in Coastal Zone
Effective Date 07/03/2021
Municipal Code Accessory Dwelling Units (Title III, Div. 1, Chapter 4, Section B, Part 2, 69.05)
Code Link
Authority Planning and Building Department


Humboldt County defines and treats tiny homes differently depending on whether they are installed on a permanent foundation or on wheels:

  • A Tiny House on Foundation (THOF) is built or installed on a permanent foundation.
  • A Moveable Tiny House (MTH) is built on a chassis and meets park model RV standard (ANSI). It may also be made to meet building codes (CBC or alternative) once installed at a site.
  • Both are classified as a permanent, year-round dwelling if used as accessory dwelling units.

A Tiny House on a Foundation (THOF) is treated like a small stick-built house where it is not used as an Accessory Dwelling Unit (ADU). That means it is allowed wherever a single-family dwelling is allowed if it meets current codes.  If a THOF is used as an ADU, (accessory to another single-family unit on the same parcel), it qualifies for streamlined permitting and special allowances provided it meets certain conditions. Those conditions are specified in the 2020 ADU ordinance for inland locations (HCC 69.05), and California Govt. Code 65852.2 for 3 parcels in the coastal zone. (See also ADU Checklists).

A Movable Tiny House (MTH) (tiny house on wheels and/or as an RV built on a chassis) is allowed as permanent ADU in inland areas of Humboldt County. MTHs are not allowed as permanent dwellings in the Coastal Zone at this time. They continue to be allowed in Manufactured Home Parks and Special Occupancy Parks.

Need More Info? – Tiny House Fact Sheet 2020

Key Contacts

Planning and Building Department
3015 H Street
Eureka, CA  95501
(707) 445-7541



Updated:  Loran – September 2021

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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