Renting in Sonoma County: the rules that apply

Each rule below is marked Sonoma County code or CA state law and links to the section it comes from (checked October 2026). General information, not legal advice.

Sonoma County's code applies in the unincorporated areas of the county. Cities in Sonoma County have their own codes and their own pages.

Sonoma County code County rule: mobile home space increases above 70% of CPI change or 4%, whichever is less, in 12 months must follow ordinance procedures.

All 11 Sonoma County rules on rent increases, with the code text and the state law underneath →

Sonoma County code County rule: in covered units, unpaid rent above 1 month's rent is a just cause; after 2 in a calendar year, any default counts.

All 3 Sonoma County rules on eviction and just cause, with the code text and the state law underneath →

Sonoma County code County rule: a covered no-fault termination pays the monthly fair market rent or the actual monthly rent, whichever is more.

All 4 Sonoma County rules on relocation payments, with the code text and the state law underneath →

Sonoma County code County rule: file every termination notice served on or after January 1, 2025 on the county Tenant Protections Portal within 3 days.

All 7 Sonoma County rules on notices, with the code text and the state law underneath →

CA state law Sonoma County has no rule of its own on this, so California law applies. Security deposit cap: One month's rent, on top of the first month's rent (Civ. Code § 1950.5(c)(1), (c)(6)). Deposit return deadline: 21 calendar days after the tenant moves out, with an itemized statement of any deductions (Civ. Code § 1950.5(h)(1)). California security deposit law — the full state rule →

CA state law Sonoma County has no rule of its own on this, so California law applies. Retaliation protection period: For 180 days after a tenant complains about habitability (to the landlord or an agency), the landlord may not evict, raise rent or cut services in retaliation (Civ. Code § 1942.5(a), (b)). Retaliatory eviction in California — the full state rule →

CA state law Sonoma County has no rule of its own on this, so California law applies. Lockouts and self-help eviction banned: A landlord may not change locks, remove doors or windows, or remove the tenant's belongings to force a tenant out (Civ. Code § 789.3(b)). Utility shutoffs banned: A landlord may not cut off water, heat, electricity, gas or other utilities to force a tenant out (Civ. Code § 789.3(a)). Tenant harassment and lockouts in California — the full state rule →

CA state law Sonoma County has no rule of its own on this, so California law applies. Duty to keep the unit habitable: The landlord must deliver a unit fit to live in and repair conditions that make it untenantable (Civ. Code § 1941). Repair and deduct: A tenant may make a repair the landlord neglects and deduct the cost from rent, up to one month's rent, no more than twice in any 12 months (Civ. Code § 1942(a)). Habitability and repair-and-deduct — the full state rule →

CA state law Sonoma County has no rule of its own on this, so California law applies. Landlord entry notice: Reasonable written notice, presumed to be 24 hours, and entry only during normal business hours (Civ. Code § 1954(d)(1), (e)). Landlord entry notice in California — the full state rule →

Sonoma County code County rule: coastal vacation rentals need a zoning permit and a vacation rental license, only in detached single-family homes, 1 per parcel.

All 4 Sonoma County rules on short-term rentals, with the code text →

Sonoma County code An increase above the regular annual cap needs the extra procedures in the chapter. An increase above 300% of the CPI change automatically requires meet-and-confer and arbitration to show good cause.

All 10 Sonoma County rules on mobilehome park rent, with the code text →

Sonoma County's code also has these chapters. We have not summarized their values on this page yet; read them in the library.

• Mobilehome Park Space Rent Stabilization (Ch. 2, Art. XIX) — mobilehome park spaces only