Buying a Teardown to Build in Marin, San Francisco or Wine Country

Buying a teardown means paying for a house you plan to demolish so you can build a new one on its lot, and the deal only works if you can get both a demolition permit and an approval for the replacement home. In San Francisco, demolishing a residential unit generally needs a conditional use authorization from the Planning Commission unless the project qualifies for an exemption. In the cities and counties covered by the state’s Housing Crisis Act, a housing project that demolishes homes must also replace at least as many units as it removes.

Those rules, plus historic review, tenant history, site conditions and local design review, decide what a teardown is worth. This post sets out what to check before you write an offer in San Francisco, Marin, Napa or Sonoma, and how to structure the contract so you have time to check it. For the general trade-offs of building new, see our post on new construction versus existing homes.

What you’re really buying

With a teardown, the price reflects the land and what you can build on it, not the house. Two lots with similar houses can be worth very different amounts if one allows a larger replacement home, has better access or avoids a lengthy review.

Start your analysis with what can be built: the zoning envelope, setbacks, height limits and any floor-area limits. Then add the time and cost of approvals, demolition, site work and utilities. A lot that needs a public hearing, a historic study or a long driveway can cost a year or more of carrying costs before construction starts.

In some cases, a remodel that keeps part of the structure is a better route than full demolition. Ask your architect to price both before you decide.

State law: replacing the housing you remove

The Housing Crisis Act’s demolition rules are in Government Code section 66300.6. An “affected” city or county, the statute’s term for the jurisdictions it covers, may not approve a housing development project that demolishes residential units unless the project creates at least as many units as it demolishes. Ask the local planning department whether the rule applies there. The project must also include at least as many units as the site’s highest count in the previous five years.

Stricter rules apply to “protected units,” a term defined in nearby sections that covers rent-restricted and rent-controlled housing and housing occupied by lower-income households. Those units must be replaced, and lower-income occupants are entitled to relocation benefits and a right of first refusal on a comparable unit, with exceptions.

Occupants may stay until six months before construction begins and must get written notice at least six months ahead. The statute also says it doesn’t override a local ordinance that is more protective. For a buyer, this makes the property’s rental history as important as its zoning; our guide to buying a tenant-occupied property covers the leases and estoppels to request.

San Francisco: Planning Code 317 and 317.2

San Francisco reviews residential demolition under Planning Code section 317, and since February 7, 2026, also under section 317.2. That newer section, created by Ordinance No. 3-26, implements the Housing Crisis Act’s replacement and tenant rules in the city. The Planning Department’s fact sheet, last updated July 22, 2026, summarizes both.

When a project counts as a demolition

The fact sheet defines a residential demolition to include a major alteration that removes 50% or more of the combined front and rear facades and 50% or more of the horizontal elements, measured by surface area. A “remodel” that crosses those thresholds is reviewed as a demolition.

Conditional use authorization

Unless exempt, a project that demolishes a residential unit needs conditional use authorization at a public Planning Commission hearing. It must meet six of eight criteria, which cover open code violations, historic status, rent-controlled units, affordable housing, two-bedroom units, rental status, net gains in units and bedrooms, and recent tenant move-outs. A criterion that doesn’t apply counts as met.

Outside the city’s Priority Equity Geographies special use district, an exemption generally requires that no unit is tenant-occupied or protected, there is no recent eviction or buyout history, the building isn’t historic, the project adds at least one net unit, and a neighborhood meeting has been held. In practice, a one-for-one replacement of a single-family house doesn’t add a unit, so check early whether your plan needs a hearing.

Replacement units and tenants

Under section 317.2, the new project must include at least as many units as were demolished or existed in the last five years. A comparable replacement unit has the same number of bedrooms and full bathrooms and at least 90% of the old unit’s floor area. Tenants receive relocation payments matching Ellis Act amounts, and a private right of action enforces the rules.

Our San Francisco real estate guide and the post on buying a San Francisco Victorian cover the city’s older housing stock, where these rules come up most.

Historic review: the age of the house matters

Historic review happens under the California Environmental Quality Act. San Francisco Planning’s preservation FAQ says all buildings constructed over 50 years ago may be potential historic resources, and it lists demolition among the changes that can require review. If a project could cause a substantial adverse change to a historical resource, the FAQ says an environmental impact report is required.

The city’s Property Information Map shows each address’s historic status, and Preservation Bulletin No. 16 explains the categories. Owners of some buildings may need to submit historical documentation. For designated Article 10 landmarks, the city can place a moratorium of up to one year on demolition permits.

Outside San Francisco, each city and county runs its own historic screening as part of its CEQA review. Ask the planning department whether the house has been surveyed and what age triggers a historic evaluation there.

Marin, Napa and Sonoma: design review, fire and septic

North of the Golden Gate, the main questions are usually design review, hillside and fire rules, and wastewater. Marin’s towns and the county each run their own design review, and some have view or story-pole requirements; see our guides to renovation and design review in Marin and Marin view ordinances.

In rural Napa and Sonoma, a replacement home may depend on septic capacity, well yield and fire-access standards. Ask the county whether a new septic design would cap the number of bedrooms before your architect starts. Our posts on well and septic inspections and building lots and ADUs in Sonoma County cover those checks.

If the lot is in a fire hazard severity zone, the zone affects how the new house is built and how the site is maintained. Our fire hazard zone guide explains how to look up a parcel. A lot that could hold more than one home may also qualify for an SB 9 lot split, subject to its tenant and fire-zone limits.

Site work: soils, asbestos and utilities

• Soils and slope. A new foundation needs a geotechnical report on many hillside lots. Read our post on geotechnical reports for hillside homes.
• Asbestos notice. Under its Regulation 11, Rule 2, the Bay Area Air District requires notification for every demolition, regardless of asbestos content, at least 10 business days ahead. For residential buildings with four or fewer units, a 72-hour notice is available for an extra fee. Outside the Bay Area Air District’s boundaries another air district handles notices, so confirm which agency covers the parcel. Older homes often need an asbestos survey and abatement first, so budget for both.
• Utilities. Arrange for gas and electric service to be disconnected before demolition, and confirm sewer or septic abandonment requirements with the local agency.
• Trees and access. Many jurisdictions protect certain trees, and construction traffic needs legal access. Our post on private road maintenance agreements covers shared roads.

Structuring an offer on a teardown

1. Ask for a longer investigation period. Feasibility work takes longer than a home inspection. Negotiate enough time for a planning pre-application meeting and an architect’s massing study.
2. Request the property file. Ask for permits, plans, surveys, soils reports, septic records and the tenancy history for the last five years.
3. Read the disclosures for hazards. The natural hazard disclosure report flags fire, flood and seismic zones that affect what you can build.
4. Get the zoning in writing. A planner’s email or a zoning letter is more reliable than a listing’s description of what can be built.
5. Budget for time. Include carrying costs for the approval period, not just construction.
6. Decide before removing contingencies. If the demolition path depends on a hearing or a historic study you can’t finish in time, renegotiate or walk away.

The California residential purchase agreement sets the default contingency periods, and you can negotiate different ones. Diamond may refer you to partners we work with; you’re free to choose any provider.

This post is general information, not legal advice. Before you commit to a lot, ask a California land-use attorney how the demolition and replacement rules apply to it.

Questions people ask

Do I need a permit to tear down a house in San Francisco?

Yes. Demolishing a residential unit generally needs conditional use authorization at a Planning Commission hearing unless the project meets the exemption criteria, followed by a demolition permit. Section 317.2 adds replacement and tenant requirements as of February 7, 2026.

Does California require me to replace the house I demolish?

In the cities and counties it covers, Government Code section 66300.6 bars approving a housing development project that demolishes units unless it creates at least as many units as it removes. Stricter rules apply to protected units, such as rent-controlled housing or homes occupied by lower-income households.

Is a house over 50 years old automatically historic?

No. San Francisco Planning says buildings over 50 years old may be potential historic resources, which can mean added review. Whether a building is actually historic depends on the evaluation.

How much does it cost to tear down a house?

It varies with the house’s size, asbestos and lead abatement, site access and utility work. Get a demolition contractor’s bid during your investigation period, and add abatement and permit fees.

Can a big remodel count as a demolition?

In San Francisco, yes. A major alteration that removes 50% or more of the combined front and rear facades and 50% or more of the horizontal elements is treated as a residential demolition.

Do I need to notify the air district before demolition?

In the Bay Area Air District, every demolition needs notice at least 10 business days ahead, with a 72-hour option for buildings of four or fewer units at an extra fee.

If you’re looking for a lot or a house to replace in Marin, San Francisco or wine country, talk with Diamond about your search, and we’ll help you line up feasibility checks before you write an offer.

Sources & notes

• California Public Law: Government Code section 66300.6
• San Francisco Planning: Tenant protections related to residential demolitions and renovations (Section 317.2 fact sheet)
• San Francisco Planning: Historic preservation FAQs
• Bay Area Air District: Asbestos demolition and renovation notifications

Last reviewed October 2026 by Matthew Martinez.