Multifamily and Duplex Properties for Sale at The Sea Ranch: Zoning and Rent Rules

What multifamily at The Sea Ranch looks like

"Multifamily" at The Sea Ranch means something narrow: clustered condominium projects such as the original Condominium One, a small number of rental apartments including Sea Ranch Apartments, and single homes on lots that a few owners lease long term. Most homes are second homes or vacation rentals. A buyer looking for income property here is usually buying a condominium or a single lot, not an apartment building. For two to four units, read financing 2-4 unit properties; for larger buildings, see apartment building loans.

Where the zoning allows it

Two sets of rules decide unit count, and both must allow a project.

Affordable housing. The County’s Land Use Element says all deed-restricted affordable units in the Coastal Zone are at The Sea Ranch and Bodega Bay. It cites 45 affordable rental units required for a 300-unit expansion of The Sea Ranch. Policy C-LU-6o supports rehabilitating and maintaining Sea Ranch Apartments.

ADUs and SB 9. County law allows ADUs, but the TSRA one-residence rule counts a guest suite without a kitchen as part of the main house. Separate second units on lots under three acres can conflict with the covenants, so ask TSRA and a lawyer before planning one. The County’s census layer lists no Sea Ranch urban cluster, and Permit Sonoma’s SB 9 page requires one, so SB 9 likely does not apply. TSRA also bars splitting lots under two acres. See our ADU investment guide and SB 9 lot split guide.

Rent rules: state rent cap plus County tenant protections

AB 1482. The Attorney General’s rent cap page, updated July 16, 2026, puts Sonoma County under "All Other Counties," with covered units allowed up to 8.6% for increases from August 1, 2026 through July 31, 2027. Many Sea Ranch homes and condominiums owned by individuals may be exempt when the owner gives the required notice; check each unit.

County Ordinance 6496. The Sea Ranch is unincorporated, so the County’s tenant ordinance applies to long-term rentals:

• Just cause begins with lawful occupancy, with transient stays excluded.
• No-fault terminations require relocation of the greater of HUD Fair Market Rent for the Santa Rosa area or actual rent.
• Termination notices go on the County portal within three days, per the landlord page.
• Deed-restricted affordable units, such as the required Sea Ranch affordable rentals, are brought under its rules.

See our AB 1482 guide and just cause eviction guide.

The Sea Ranch rental property rules

• Vacation rentals (County). Permit Sonoma’s vacation rental page lists the Coastal Zone as allowing whole-home vacation rentals with a zoning permit, a certified property manager, a TOT number and a license. ADUs cannot be vacation rentals, a rule the Local Coastal Plan repeats in Policy C-LU-4g.
• Leasing (TSRA). Under §3.02(c)(3) of the Restrictions, owners may lease, but tenants and guests are bound by all the Restrictions. We did not review separate TSRA rental rules or fees.
• Assessments (TSRA). Article VI of the Restrictions sets annual maintenance assessments, with a base cap adjusted for cost of living. Unpaid assessments can become a lien. Get the association’s current figures and a payoff certificate in escrow.
• Transfer tax. Only the County’s $0.55 per $500.

Water, sewer, septic and coastal weather

Water. The Sea Ranch Water Company, per Permit Sonoma’s referral list.

Sewer. The Sea Ranch Sanitation Zone bills per equivalent dwelling, and its 2026 newsletter set a public hearing on a $1,966-a-year-per-ESD rate for FY 2026-27 (effective July 1, 2026 if adopted); confirm the current rate with Sonoma Water. Many homes outside it use septic, and Sonoma Water reports it has re-sided both treatment buildings against coastal weather.

Buildings. Condominium buildings with elevated decks and walkways need SB 721 balcony inspections if three or more units, and wind-exposed wood siding and decks deserve a close inspection. Ask for a seismic retrofit review for raised buildings.

Underwriting a Sea Ranch multifamily purchase

1. Read the Restrictions and any condominium project documents before counting units or planning additions.
2. Get a Design Committee estoppel certificate on the lot’s compliance, available under §4.06 for a fee.
3. Decide long-term versus vacation rental use, and confirm County vacation rental permits and TOT registration if nightly income is in the pro forma.
4. Classify long-term units under AB 1482 and Ordinance 6496; model increases at or below 8.6% where covered.
5. Collect leases and estoppel certificates, plus TSRA assessment status.
6. Rebuild expenses with reassessed taxes, TSRA assessments, sanitation or septic costs and coastal insurance in our rental property analysis.

Questions people ask

Sources & notes

1. Local Coastal Plan Land Use Element, 2023 and certification notice
2. Chapter 26C, Article XII PC District
3. The Sea Ranch Restrictions with Article III and Articles VI to IX (private covenants, published by TSRA)
4. Ordinance 6496 and landlord page
5. California Attorney General, rent caps
6. Permit Sonoma vacation rentals, SB 9 page and census layer
7. Sea Ranch Sanitation Zone newsletter, 2026 and Permit Sonoma referral list
8. Sonoma County Recorder

Note: TSRA documents are private covenants published by the association, not government sources. We did not read the Sea Ranch Rules, Design Committee rules, any TSRA rental policy or condominium project declarations, or verify how TSRA treats ADUs under state law. The AB 1482 exemption is summarized generally, and the description of the housing stock, including Condominium One, is a general observation. See also our Sonoma County multifamily guide and Sonoma County commercial guide.

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

Related: The Sea Ranch real estate guide · Commercial real estate at The Sea Ranch · Multifamily investing guide · Investor services