LedgeX Research
Plain-language research on homes, lots and the rules around them. Every figure cites its source, and every piece says what it can’t establish.
Will an ADU Raise Your Property Taxes? What California Law and San José’s Records Show
Building an ADU reassesses only the new unit. We traced the rules from Proposition 13 to the 24 distinct tax rates across San José’s 204 tax rate areas, and tested 738 San José ADU permits.
Read the research- $1,147 to $1,316
- Added tax a year per $100,000 of ADU value in San José
- 88%
- Of active San José ADU permits valued at square footage times a flat rate (651 of 738)
- 204
- Tax rate areas in San José, sharing 24 distinct total rates
- 0
- State property-tax exclusions for ADUs in effect
Santa Clara County rate book, San José permit data
Guides for your lot.
What a lot allows, what an ADU costs in taxes and fees, and what public records can’t tell you. New to ADUs? Read these four in order.
ADUs 101: a plain-language guide
What state law guarantees in 2026, what cities still control, and why a legal ADU might not fit.
Can you build an ADU on your California property?
State rules, city rules and the lot itself. How to check each, and where public records run out.
San José ADU requirements: size, setbacks, fire access
The City and State rule sets side by side, and the fire and water questions that rule out most designs.
Will an ADU raise your property taxes?
Only the new unit is reassessed. San José tax rates, permit data and when the extra bills arrive.
Investigations.
The money, risk and policy behind California property values, traced to the public record.
- $10B of $36.25B
The part of the $36.25 billion that taxpayers repay
California Just Approved More for Housing Than Hawaiʻi’s Entire State Budget: Props 1 and 37 Explained
Only $10 billion of it is taxpayer debt. What the two measures do, who pays, and what they could mean for new-home buyers.
- $178
General fund bank account, week of Sept. 21, 2026
Hollister’s Financial Emergency: How a City Ran Out of Money It Could Spend
The general fund ran out of cash while development-fee funds held tens of millions. Then the city borrowed $18 million of it.
- 27.7%
City office vacancy in Q3 2026, down from a 36.9% peak
Has San Francisco Real Estate Already Priced In the AI Revolution?
AI firms lead an office recovery and rents are rising fast. Repeat-sales home prices tell a more measured story.
- $250k
Federal flood insurance building limit for a single-family home
Was the Water Already in the Price? Newport Beach Flooding and Coastal Real Estate
How flood insurance, lenders, public spending and buyer expectations shape coastal property values.
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Each new guide and investigation from LedgeX Research, sent when it publishes.
From the research to one lot.
The guides explain the rules. A Property File applies them to a single San José lot, with the source for every fact and a clear mark wherever records run out.