Multifamily and Duplex Properties for Sale in Upper Lake: Zoning and Rent Rules

What multifamily in Upper Lake looks like

Upper Lake’s rental stock is mostly small: duplexes and older homes split into units near downtown, apartments over Main Street storefronts, small-lot subdivision homes, and mobile homes. The Upper Lake–Nice Area Plan notes that most small-lot subdivisions approved in the planning area in recent decades were in the Upper Lake community area (p. 2-10). It also projected slow growth, between about 2,900 and 3,700 residents by 2020 depending on assumptions. For financing, see financing 2-4 unit properties and apartment building loans.

Where the zoning allows it

Upper Lake is unincorporated, so the Lake County zoning ordinance applies. The area plan designates the community area for Urban and Suburban Residential and Commercial uses, and it calls for new subdivisions that fit existing development.

Housing Element sites. The county’s 6th Cycle Housing Element lists Upper Lake as a Growth Boundary community with multifamily parcels. It projects 86 very-low-income and 160 low-income units there (Table 2-5), one of the larger allocations in the unincorporated county. Sites counted only if sewer and water were within 200 feet. Program HE-71 supports second-story housing over commercial space.

ADUs and SB 9. R2 allows one ADU or second unit per lot. See our ADU investment guide. The county articles we reviewed set no SB 9 standards, and parcels on septic, in floodways or zoned agriculture may not qualify. See our SB 9 lot split guide.

Rent rules: state law only

The Attorney General’s rent cap page does not list Lake County, so the "All Other Counties" cap applies: 7.7% for increases from August 1, 2025, and 8.6% from August 1, 2026 through July 31, 2027. No local cap appears, and we found no county just cause ordinance. State rules govern covered tenancies. See our AB 1482 guide and just cause eviction guide.

Upper Lake rental property rules

• Mobile homes. The area plan removed the old "MH" Mobilehome district from the planning area (p. 1-1). New parks now follow Article 43: a major use permit in R1-MH, R2, R3 or PDR, at least 5 acres, and no more than 10 spaces per acre. Closures require a relocation plan and impact report.
• Historic buildings. Apartments in HP-zoned buildings need a major use permit for exterior changes under Article 38, and Main Street projects follow the plan’s western town design guidelines.
• Short-term rentals. Stays of 30 days or less owe 9% TOT. The county began drafting STR rules in July 2026.
• Transfer tax. $1.10 per $1,000 under the Assessor-Recorder fee schedule.

Water, sewer and drainage

The Upper Lake County Water District draws from two wells, and the area plan encourages groundwater monitoring and conservation (p. 3-5). The plan also says cease-and-desist orders on the Northwest Treatment Facility limited further development (p. 2-10). Adding units, or converting a house to a duplex, may depend on sewer capacity, so get written confirmation from the county’s sanitation agency. Without sewer, lots in these districts need at least 40,000 square feet. The plan also reports localized flooding from poor drainage and calls for limiting development in flood-prone areas, so check elevations and FEMA zones. The 1924 downtown fire left many buildings from the 1920s rebuild, and older wood-frame buildings may warrant a seismic retrofit review. Buildings of three or more units with elevated balconies need SB 721 inspections.

Underwriting an Upper Lake multifamily purchase

1. Confirm the district and whether the parcel is a Housing Element site.
2. Get water and sewer will-serve or capacity letters, and test the legal unit count against the lot size those services require.
3. Classify each unit under AB 1482 and model increases at or below 8.6%.
4. Check flood zone, drainage and any HP or design review zoning.
5. Collect leases, the rent roll and estoppel certificates, and verify any mobile home spaces are permitted.
6. Rebuild expenses with reassessed taxes and current insurance in our rental property analysis.

Questions people ask

Sources & notes

1. Upper Lake–Nice Area Plan (posted draft)
2. Lake County 6th Cycle Housing Element 2019–2027
3. Lake County Zoning Ordinance: index, 11 R2, 12 R3, 19 C2, 38 HP, 43
4. California Attorney General, Rent Caps
5. Lake County STR committee news, TOT Ordinance, Assessor-Recorder fees

Note: The area plan copy is a draft without an adoption date, and its sewer description may be outdated. Confirm current capacity with the county.

General information, not legal or tax advice. Last reviewed October 2026 by Matthew Martinez.

Related: Upper Lake real estate guide · Commercial real estate in Upper Lake · Multifamily investing guide · Investor services