Mobile Home Rent Stabilization Ordinance

The Mobile Home Rent Stabilization ordinance (MRSO) can be found in Chapter 9101 of the Humboldt County Code. It outlines the roles and responsibilities of the County, mobile home park owners, and park residents.  Download a copy here: MRSO (PDF)

What does it do?

The MRSO limits the frequency and amount of space rent increases. It provides a process for residents to petition for lower rent if services are reduced. It also provides a process for park owners to petition for fair returns. It reinforces tenants' rights and the prohibition against retaliation for exercising those rights.

The MRSO requires a Resident Representative in each park to serve as a liaison with the County, allowing the free flow of information. The MRSO is a self-funded ordinance that requires participants to pay a monthly fee for its ongoing administration.

Allowable Rent Increases

No rent increases may be charged unless authorized in the ordinance.  

  • Annual increases, after May 1, 2017, will be based on 100% of the increase in Consumer Price Index (CPI) for all items for all urban consumers for the San Francisco-Oakland-Hayward area as reported by the Department of Labor, Bureau of Labor Statistics, rounded to the nearest quarter percent. 
  • Rent increase upon sale or move-in of a new tenant, maximum 5%.
  • Rent increases for new capital improvements, with the approval of a majority of the tenants.
  • Increase due to the right of fair return, with proper notice.

Each park completes an annual registration that a county monitor reviews to ensure compliance. 
2026 Registration Form (PDF)

CPI in 2026

The Consumer Price Index for 2026 3.05%, which means that a landlord may raise space rents in a park anything from 0% up to 3.0% in 2026. Read this Official CPI Notice (PDF) for more information. The rate was determined using these data from the Bureau of Labor Statistics (PDF).

Of Note...

The exemption from rent control based on having a long-term lease was repealed by function of law on January 1, 2025. Since then, even tenants with multi-year leases can benefit from the MRSO. 

Links to State of California Information

All mobile home parks are subject to the California Mobile Home Residency Law (Civil Code 798 et seq.).
California Mobile Home Residency Law 
Updates to the MRL Effective 1/1/2026

Mobile Home Conversion Ordinance

In 2016, the County adopted a Mobile Home Conversion Ordinance. This ordinance addresses steps that must be taken upon the sale of a park. The main consideration in the ordinance is the recognition that residents who are displaced by the conversion of a park to another use may need to be compensated. 
Conversion Ordinance (PDF)

MRSO History

In 2016, Humboldt County voters passed Measure "V", adopting an ordinance to regulate rent increases for spaces in mobile home parks with ten or more spaces in the unincorporated areas of Humboldt County. On December 13, 2016, the Board of Supervisors certified the election results, thereby incorporating Ordinance 2569 into the Humboldt County Code. Measure V obligates the County to administer the ordinance. On October 22, 2024, the Board of Supervisors adopted the Implementing Guidelines. 
Implementing Guidelines (PDF)