Buying a Home in Santa Clara County, CA: San Jose Transfer Tax, Measure E & ADUs
San Jose layers its own transfer tax plus a steep Measure E surcharge on high-value sales, and the county has an unusually active ADU permitting environment.
Santa Clara County — anchored by San Jose, the largest city in Northern California — has a few characteristics that matter to an unrepresented buyer and don't show up in a generic California guide: San Jose's own transfer tax on top of the state rate, active earthquake fault zones running through populated areas, a market shaped heavily by tech-industry compensation, and an unusually active ADU permitting environment.
What’s the transfer tax in Santa Clara County?
The state base is $1.10 per $1,000 of sale price, but the City of San José — a charter city — adds its own $3.30 per $1,000 city tax, and sales above $2.3M inside San Jose can also owe the tiered Measure E surcharge.
A $1,500,000 sale in San Jose comes to $1,650 base plus $4,950 city tax, about $6,600 total, customarily split 50/50 between buyer and seller (negotiable). Other Santa Clara County cities — Palo Alto, Mountain View, Sunnyvale, Cupertino — do not currently have a Measure-E-style added transfer tax as of 2026, though Sunnyvale has periodically considered placing one on the ballot. See below for how Measure E works on higher-value San Jose sales.
What is Measure E, and when does it apply to a San Jose purchase?
Measure E is a further, progressively-tiered tax San José voters approved in 2020 on top of the base and standard city transfer tax, applying only to sales above $2,300,000 (as of July 1, 2025).
The tiers: $2.3M–$5M is taxed at 0.75% ($7.50/$1,000); $5M–$10M at 1.0% ($10.00/$1,000); $10M+ at 1.5% ($15.00/$1,000). A $6,000,000 San Jose sale owes roughly $60,000 in Measure E alone (1.0% tier), on top of the $6,600 base and $19,800 standard city tax — about $86,400 in combined transfer taxes before other closing costs. Measure E is customarily split 50/50 between buyer and seller, though negotiable, and funds homeless assistance and affordable-housing programs. Its legal status isn't fully settled: a 2026 statewide ballot initiative under discussion could force local special taxes like Measure E to clear a two-thirds voter threshold retroactively, or bar charter cities from levying transfer taxes above the state rate. Always confirm current applicability with escrow/title at the time of a specific transaction rather than assuming the rates above are permanent.
Are there earthquake fault zones to check in Santa Clara County?
Yes — the Hayward Fault and the Calaveras Fault both run through the county and are regulated under the Alquist-Priolo Earthquake Fault Zoning Act.
If a specific property sits within a mapped Alquist-Priolo zone, the seller must disclose that under PRC §2621.9 — construction of habitable structures directly on an active fault trace is restricted, and lenders/insurers may ask additional questions. This is a parcel-specific determination, not a whole-city designation — cities and unincorporated areas along the eastern side of the county (nearer the fault traces) are more likely to have properties inside a mapped zone than those further west, but always rely on the actual NHD report for the specific address rather than a general neighborhood assumption.
How big of an ADU can I build on a Santa Clara County property?
It depends on the city and lot size — San Jose offers both a City Development Standards path (up to 1,000–1,200 sq ft depending on lot size) and a State Development Standards path (up to 800 sq ft on any lot), plus a 500-sq-ft JADU option carved from existing living space.
State law (Government Code §65852.2) requires cities to permit ADUs on most residential lots, caps parking requirements (none required within a half-mile of a major transit stop), sets a maximum 60-day permit review window once an application is complete, and exempts ADUs from owner-occupancy requirements (though a JADU still requires the owner to occupy either the main home or the JADU). San Jose's typical detached-ADU height limit is 16 feet with a 4-foot minimum side/rear setback — verify current figures against the city's ADU checklist, since local ordinances get amended more often than state law. A property advertised with 'ADU potential' should be evaluated against actual lot size and setbacks, and verify any existing ADU was actually permitted via the city's ADU Universal Checklist/permit history — an unpermitted ADU can complicate financing, insurance, and resale.
Is there rent control in Santa Clara County?
It varies significantly by city, unit count, and construction date — San Jose has two separate ordinances with different scopes, Mountain View has the strictest local rules in the county, and Palo Alto and Sunnyvale rely mostly on statewide AB 1482.
San José's Apartment Rent Ordinance caps rent increases only for 3+ unit buildings first occupied before September 7, 1979 (about a third of the city's rental stock), currently one increase per 12 months capped at 5%; its separate Tenant Protection Ordinance covers any 3+ unit building regardless of construction date (plus unpermitted units) with 13 defined just-cause eviction reasons — so a 1985-built San Jose 3-plex isn't subject to the rent cap but is subject to just-cause rules. Mountain View's Community Stabilization and Fair Rent Act (Measure V) gives 3+ unit buildings built before February 1, 1995 both a CPI-based rent cap (historically 2-5%/year, set annually — verify the current figure) and just-cause protection; buildings built 1995–2016 get just-cause only. Palo Alto and Sunnyvale have no local rent cap (AB 1482 only), though Sunnyvale requires relocation assistance for no-fault evictions. Cupertino has no confirmed local ordinance. Before offering on a property with existing tenants, confirm the exact city, unit count, and construction/occupancy date — these three facts determine which ordinance, if any, controls your ability to raise rent or recover the unit after closing.
Disclosure landscape
- Alquist-Priolo Earthquake Fault Zone disclosure applies to properties within the mapped Hayward or Calaveras fault zones, required on the NHD report for the specific address.
- Measure E's legal status is not fully settled as of 2026 — confirm current applicability with escrow/title at the time of a specific transaction on any San Jose sale above $2.3M.
- Verify any existing ADU was actually permitted via the city's ADU Universal Checklist/permit history — an unpermitted ADU can complicate financing, insurance, and resale.
- Rent-control and just-cause coverage depends on the exact city, unit count, and construction/occupancy date — verify with the applicable city rent program rather than assuming.
Frequently asked
Does Measure E apply to every home sale in San Jose?
No — only to sales above $2,300,000 (as of July 1, 2025). Below that threshold, San Jose sales owe only the state base rate ($1.10/$1,000) plus the city's standard transfer tax ($3.30/$1,000).
Is my San Jose triplex subject to rent control?
It depends on when the building was first occupied. San José's rent-cap ordinance (ARO) only covers 3+ unit buildings first occupied before September 7, 1979 — but its separate just-cause eviction ordinance (TPO) covers any 3+ unit building regardless of age.
Can I add an ADU to a property I'm buying in San Jose?
Likely yes, subject to lot size and setbacks — San Jose allows up to 1,000–1,200 sq ft under its City Development Standards or up to 800 sq ft under the state standard, plus a 500-sq-ft JADU option. Verify current setback and height rules against the city's ADU checklist before counting on a specific size.
This is educational guidance, not legal advice. Consult a California real estate attorney for legal questions specific to your transaction.