Colusa County Rent Increase & Rent Control Guide 2026–2027: Colusa, Williams & Unincorporated Areas
Colusa County rent rules depend on the exact jurisdiction and housing type. See the verified 8.6% California Tenant Protection Act ceiling, Colusa and Williams versus unincorporated areas, notice rules, local housing resources and practical compliance steps.
The short answer
For Colusa County housing covered by California's Tenant Protection Act, the California Attorney General's current chart places the county in the 'All Other Counties' group and lists an 8.6% statewide ceiling for increases taking effect August 1, 2026 through July 31, 2027. The statutory formula remains 5% plus the applicable cost-of-living change, capped at 10%, and the property still must be checked for coverage or an exemption.
As verified September 23, 2026, the Attorney General's current local rent-cap chart does not list Colusa County, the City of Colusa or the City of Williams for a general long-term residential rent-stabilization percentage. The current County code and the municipal-code and housing resources linked by the two cities were also reviewed and did not identify one general local apartment or house rent-cap percentage. This is a carefully scoped current-source finding, not a permanent guarantee: local laws can change, and mobilehome, subsidized, deed-restricted, emergency or property-specific rules can require separate analysis.
Start with jurisdiction: Colusa County has two incorporated cities
California Secretary of State records for 2026 identify two incorporated cities in Colusa County: Colusa and Williams. The same current state registration report separately identifies an unincorporated area. That distinction matters because a rental inside either city should be checked against that city's current code and housing resources, while properties outside city limits generally start with Colusa County departments and the County code for local-government questions.
Communities such as Arbuckle, Maxwell, Princeton, Grimes and Stonyford are served through County facilities and planning resources rather than being separate incorporated cities. A mailing address or community name is not enough to establish jurisdiction, so renters, owners and property managers should confirm the actual parcel or city boundary before relying on a local rule.
California Tenant Protection Act: 8.6% for the current Colusa County period
The California Attorney General's current statewide chart lists an 8.6% Tenant Protection Act ceiling for the 'All Other Counties' category for increases taking effect August 1, 2026 through July 31, 2027. Colusa County is not one of the separately calculated Los Angeles, Riverside, San Bernardino, San Diego or San Francisco-area county groups, so 8.6% is the current state-law ceiling for covered Colusa County housing during that effective-date window.
The 8.6% number is not an automatic right to raise every rent by that amount. The Attorney General explains that the statewide cap covers most California rental housing more than 15 years old, while statutory exemptions can include certain newer housing, qualifying individually owned single-family homes or condominiums when the required exemption conditions are met, some owner-occupied duplexes, dormitories and certain restricted affordable housing. Always resolve coverage before applying the percentage.
No general local Colusa County, City of Colusa or Williams rent-stabilization percentage was verified
The Attorney General's current local rent-increase chart summarizes many California city and county rent-stabilization ordinances and does not list Colusa County, the City of Colusa or the City of Williams. For this September 23, 2026 verification, Max Rental Tools also reviewed the County code portal, the City of Colusa housing and municipal-code resources, and the City of Williams housing page and municipal-code portal linked from the official City website. No general long-term residential rent-control percentage for ordinary apartments or houses was identified in those current primary-source pathways.
That finding should not be converted into a blanket statement that no local protection can ever apply. The Attorney General expressly warns that its chart is informational, that local governments may have tenant protections other than numerical caps, and that mobilehome-space rent-control ordinances may not be included. Recheck the exact City or County source before serving or challenging an increase and separately review subsidized housing, deed restrictions, mobilehome arrangements, lease restrictions and any emergency protections in effect on the proposed increase date.
City of Colusa and City of Williams have separate local-government resources
The City of Colusa maintains its own Planning and Building Department, housing resources and municipal code. Its housing page links residents to Colusa County housing assistance, the Regional Housing Authority, HUD, state housing resources and California Rural Legal Assistance. Properties actually within Colusa city limits should therefore be checked against City resources in addition to statewide law.
The City of Williams likewise maintains its own Planning program, Housing Element and municipal code, and its official website directly links the City code portal. Williams' current housing page identifies the 2020–2028 Housing Element and City planning contacts. For a property inside Williams, use the City code and planning/housing contacts rather than assuming an unincorporated County rule controls.
Unincorporated County rules can matter even when they are not rent caps
Colusa County's current code states that it includes legislation through Ordinance 850, passed April 7, 2026. Its Chapter 22 regulates the use and occupancy of mobile homes in unincorporated areas and expressly says that chapter does not apply to mobile homes in parks licensed under the state mobilehome-park framework. The chapter addresses permits, use and occupancy rather than publishing a general residential rent-increase percentage.
That distinction is important for rural properties. A manufactured or mobilehome arrangement may trigger land-use, park, state Mobilehome Residency Law or other specialized rules even though the ordinary County code chapter does not create a general apartment rent cap. Determine whether the resident rents the home itself, rents only a mobilehome space, lives in a licensed park, or occupies a mobilehome outside a licensed park before choosing the legal framework.
Maxwell and other unincorporated communities require County-level verification
Maxwell is one example of why county-level research matters. Colusa County's Maxwell Community Plan specifically discusses temporary workforce housing, long-term economic strategies and community changes associated with the Sites Reservoir project. That planning work does not itself establish a rent cap, but it shows that housing conditions and local land-use planning can change in an unincorporated community even without a separate city government.
For rentals in Maxwell, Arbuckle, Princeton, Grimes, Stonyford or other unincorporated areas, begin with the exact address, the County code, County Planning and the current Housing Element. Do not treat the community name as if it were a separate incorporated city with its own rent ordinance.
Written notice and timing are separate compliance requirements
California's Attorney General states that a residential rent increase must be delivered through formal written notice; a call, text or email by itself is not enough. For an increase of 10% or less, landlords generally must provide at least 30 days' notice before the increase can take effect. For an increase of more than 10%, the general notice period is 90 days. The notice requirement is separate from the percentage limit.
For a Tenant Protection Act-covered Colusa County rental during the current 8.6% period, the state cap will ordinarily be more restrictive than the over-10% notice category. But a proposed increase can still fail because of the effective date, service method, lease timing, prior increases in the same 12-month period or a housing-program requirement. Keep percentage, coverage, timing and service as separate compliance checks.
Housing assistance, vouchers and local tenant-landlord resources
The Regional Housing Authority identifies Colusa County as one of the jurisdictions it serves and administers Housing Choice Voucher and affordable-housing programs in the region. Its Colusa County portfolio includes properties in Colusa and Williams. Voucher tenancies can require rent-reasonableness review, housing-authority approval and program-specific procedures in addition to ordinary state rent-law analysis.
The City of Colusa housing page links renters and housing providers to the County Housing Assistance Program, Regional Housing Authority, HUD, state housing resources and California Rural Legal Assistance. Colusa County's current Housing Element is another official planning resource, and the County launched full 211 service in August 2026 to connect residents with local assistance. These services do not create a general market-rent cap, but they are practical entry points for housing help and current local referrals.
Court and self-help resources in Colusa
The Superior Court of California, County of Colusa, operates a Self-Help Center at 547 Market Street in Colusa. The Court states that the service is free, has no income test and can help people with forms, procedure and legal information; its Civil Division also identifies landlord-tenant and unlawful-detainer matters as civil cases and directs self-represented parties to Self-Help resources.
The Court currently lists Self-Help hours Monday through Wednesday, 8:30 a.m. to 4:30 p.m., and a phone number of (530) 458-0598. Court schedules can change, so verify current hours before visiting. If a rent dispute progresses toward eviction, use the lawful court process rather than lockouts, utility shutoffs or removal of belongings.
Practical checklist for renters, landlords and property managers
Start with the exact street address and determine whether the property is inside the City of Colusa, inside the City of Williams or in unincorporated Colusa County. Identify the housing type—ordinary apartment or house, qualifying single-family home or condo, ADU, subsidized unit, manufactured/mobilehome, mobilehome space or other specialized housing—and record the current rent, proposed rent, proposed effective date and all increases during the prior 12 months.
For conventional covered housing, compare the proposal with the current 8.6% Tenant Protection Act ceiling for increases taking effect August 1, 2026 through July 31, 2027. Then recheck the current City or County code, verify any exemption, confirm notice timing and service, and review the lease plus any voucher, deed restriction or emergency rule. Max Rental Tools can help organize the calculation, rent ledger and rent-increase notice after the legal-rule verification is complete.
Verification date and official Colusa County resources
This cornerstone was verified on September 23, 2026. The 8.6% statewide figure is tied specifically to increases taking effect August 1, 2026 through July 31, 2027. Do not carry that percentage into a later effective-date period without checking the California Attorney General's then-current rent-cap chart.
For local verification, use the City of Colusa Planning/Housing and municipal-code resources for properties inside Colusa; the City of Williams Planning/Housing and municipal-code resources for properties inside Williams; and Colusa County Planning, Housing Element and County Code for unincorporated properties. Use the Regional Housing Authority for voucher and affordable-housing program questions and Colusa Superior Court Self-Help for court-process assistance.
Common questions
What is the maximum rent increase in Colusa County for 2026–27?
For housing covered by California's Tenant Protection Act, the California Attorney General lists 8.6% for the 'All Other Counties' group for increases taking effect August 1, 2026 through July 31, 2027. Coverage, exemptions, local rules and housing type must still be checked.
Does Colusa County have local rent control?
As verified September 23, 2026, the California Attorney General's current local rent-cap chart does not list Colusa County, the City of Colusa or the City of Williams for a general long-term residential rent-stabilization cap, and the current primary-source pathways reviewed did not identify one general percentage. Recheck the exact jurisdiction because local laws and specialized housing rules can change.
How many incorporated cities are in Colusa County?
California Secretary of State records for 2026 identify two incorporated cities in Colusa County: Colusa and Williams. The same state report separately identifies the unincorporated area.
Is Maxwell an incorporated city with its own rent ordinance?
No. Maxwell is an unincorporated Colusa County community. County planning resources, including the Maxwell Community Plan, are the appropriate local-government starting point in addition to California law.
Does the City of Williams have a separate 2026 rent cap?
The current California Attorney General local-rent-cap chart does not list Williams, and the City housing and municipal-code resources reviewed for this guide did not identify a general long-term residential rent-stabilization percentage. Recheck the City's current code before acting because ordinances can change.
Does the City of Colusa have a separate 2026 rent cap?
The current California Attorney General local-rent-cap chart does not list the City of Colusa, and the City housing and municipal-code resources reviewed for this guide did not identify a general long-term residential rent-stabilization percentage. Verify the current City code before serving or challenging an increase.
How much notice is required for a rent increase in Colusa County?
California's Attorney General states that landlords generally must provide formal written notice at least 30 days before an increase of 10% or less and 90 days before an increase of more than 10%, subject to additional tenancy-specific requirements.
Who administers Housing Choice Vouchers in Colusa County?
The Regional Housing Authority serves Colusa County and administers Housing Choice Voucher and affordable-housing programs in the region. Owners and voucher households should verify current rent approval and program procedures directly with the housing authority.
Where can Colusa County renters or landlords get court self-help?
Colusa Superior Court operates a free Self-Help Center at 547 Market Street in Colusa and currently lists (530) 458-0598. Check the Court's current schedule before visiting.
Official sources
California Attorney General — Current Statewide & Local Rent Increase CapsCalifornia Attorney General — Landlord-Tenant Issues & Rent-Increase Notice RulesCalifornia Secretary of State — Colusa County Election Map & Incorporated-City StatisticsColusa County — Current County CodeColusa County — 2020–2028 Housing ElementColusa County — Maxwell Community PlanCity of Colusa — Housing ResourcesCity of Colusa — Planning & BuildingCity of Colusa — Municipal CodeCity of Williams — Housing & PlanningCity of Williams — Municipal CodeRegional Housing Authority — Colusa County Housing ProgramsColusa Superior Court — Self-HelpContinue your check
Use the state directory for current jurisdiction-specific rules, calculate the proposed increase, then prepare the appropriate rental document only after the legal-rule checks are complete.