In brief

  • Only the ADU is reassessed. Building an ADU adds a new assessed value for the new construction. The house and land keep the values they have under Proposition 13.
  • In San José, each $100,000 of ADU value adds about $1,147 to $1,316 a year, depending on which of the city’s 204 tax rate areas the parcel sits in. Those areas share 24 distinct total rates; the most common, 1.2079%, gives $1,208.
  • The assessor uses market value, not your permit valuation. Of San José’s active ADU permits that list both figures, 88% are valued at square footage times a flat rate of $166 to $176 per square foot. That is about half the per-square-foot cost Bay Area owners reported in a 2020 survey.
  • Expect a supplemental bill after completion, or two if the ADU is finished between Jan. 1 and May 31.
  • There is no ADU tax break. A 2024 bill to exempt new ADUs for 10 years died. Separately, the solar exclusion is not available to systems that don’t qualify before Jan. 1, 2027.

Only the new part is reassessed

Proposition 13 assesses California real property at its value when it was bought or newly built, then lets that value rise by no more than 2 percent a year (Cal. Const. art. XIII A, §2). Two events reset the value: a change in ownership and new construction. When construction is finished, the assessor sets a base year value “for only that portion of the property which is newly constructed,” and everything else keeps its existing value (Rule 463); (R&T Code §71).

An ADU therefore becomes a second layer on the same parcel. The house and land stay on their old values, which for a long-time owner can be far below today’s market. The Santa Clara County Assessor is direct about it: “The existing home will not be reassessed” (Assessor). That is the most important fact for most owners. The tax you add is the tax on the ADU, not on what the whole property would sell for. From then on, the ADU’s value is adjusted each Jan. 1 by the same inflation factor as the rest of the property, capped at 2 percent (art. XIII A).

LedgeX Research · Figure 1

Two layers, one bill

A hypothetical San José home assessed at $900,000 adds an ADU the assessor values at $250,000. Only the ADU is assessed at current value.

  • Existing base year value (house and land)
  • ADU: new base year value
  • Hypothetical full reassessment
Illustration: only the ADU is added to the assessed valueHypothetical property assessed at $900,000. After a $250,000 ADU, assessed value is $1,150,000 and tax at 1.2079% rises from $10,871 to $13,891. A full reassessment at a $2,000,000 market value, which does not happen, would mean $24,158.$0$0.5M$1.0M$1.5M$2.0M$900,000$10,871 a yearassessed $900,000Before the ADU$250,000$13,891 a yearassessed $1,150,000After the ADU isfinished$24,158 a yearassessed $2,000,000If the whole propertywere reassessed (it isnot)+$3,020

How to read this. The values are invented to show the mechanics. The rate is the most common San José rate in 2025–26. Real bills also carry flat parcel charges, and an owner-occupant’s homeowners’ exemption lowers the taxable value; neither changes the ADU’s share.

Data table: illustration
CaseExisting baseADU layerAssessed valueTax at 1.2079%
Before the ADU$900,000—$900,000$10,871.10
After the ADU$900,000$250,000$1,150,000$13,890.85
Full reassessment (does not happen)——$2,000,000$24,158.00

Illustration LedgeX calc. Sources: S1 S3 S9 S20 S22. Chart and calculation: LedgeX Research.

What counts as new construction

State law defines new construction as any addition to land or improvements, or any alteration that amounts to a major rehabilitation or converts the property to a different use (R&T Code §70). The Board of Equalization’s rule adds that an alteration qualifies when it “changes the way in which the portion of the structure that had been altered is used,” and that normal maintenance and repair does not (Rule 463).

Each kind of ADU fits that definition differently. A detached ADU, or an attached addition, is new floor area, assessed at market value on completion. A garage conversion adds no square footage, but turning storage into living space changes the use of the converted area. A junior ADU carved out of a bedroom or family room is narrower still. The county says new heating, bathroom or kitchen work adds value for the modified area only, unless the space is “taken down to stud walls” and becomes the equivalent of new (Assessor).

How the unit is used doesn’t matter. “Whether the addition is for a parent or rented to earn a little extra income,” the county says, its value “remains the same” (Assessor).

LedgeX Research · Figure 2

What triggers a reassessment, and what doesn’t

Common ADU projects and later events, with the rule that governs each. Green rows reset value; gray rows do not.

What you doTax treatmentWhat happens to the assessed value
Build a detached ADUNew constructionThe ADU gets a base year value at market value as of completion. House and land keep theirs. S3 S9 S20
Build an attached ADU or additionNew constructionThe added floor area is assessed at completion; the rest of the house is not reassessed. S2 S9
Convert a garageNew construction (change of use)No new square footage, but the altered space changes use. The conversion work is assessed. S9 S20
Create a junior ADU inside the housePartialOnly the modified area’s new work (kitchen, bath, heating) is added, unless it is gutted to the studs and treated as new. S2 S20
Rent the ADU, or house a parent in itNo reassessmentUse does not change the value the assessor enrolls. S20
Repair or maintain itNo reassessmentNormal maintenance and repair is not new construction. S2 S9
Sell the ADU separately as a condominiumChange in ownershipAllowed in San José since 2024. The unit sold is reassessed at its sale price. S7 S17 S18
Sell the whole propertyChange in ownershipHouse, land and ADU are all reassessed at the purchase price. S1 S7
Put solar panels on itDepends on the dateExcluded if the system qualifies before Jan. 1, 2027, until the next change in ownership. Later systems can be assessed. S8 S14 S15

Statute / county guidance Compiled by LedgeX Research from the statutes, rules and county guidance cited in each row. General rules only; an assessor decides each case.

The rate: 204 tax rate areas, 24 distinct rates

The assessed value is half of the calculation. The other half is the rate: the 1 percent general levy plus voter-approved levies for bonds and retirement costs. Santa Clara County publishes rates by tax rate area, a patch of territory served by the same set of agencies. Its 2025–26 rate book lists 816 areas, 204 of them in the City of San José (rate book).

LedgeX extracted every San José area from the book. The 204 areas carry 24 distinct total rates, because many areas are served by the same combination of agencies. Totals run from 1.1470 percent, where Morgan Hill Unified and Gavilan College serve the south of the city, to 1.3161 percent, where bonds for the Luther Burbank elementary district, Campbell Union High and West Valley–Mission community college overlap. The most common rate, 1.2079 percent, applies in 43 areas within San José Unified. Every area carries the same 1.0732 percent in county, city and water-district levies, and none carries a land-only levy, so the full rate applies to an ADU’s value. The spread comes from school and college bonds.

For an ADU, the spread is modest but real. Each $100,000 of new assessed value adds $1,147 to $1,316 a year. The levies listed on a parcel’s annual secured tax bill show which rate applies to it.

LedgeX Research · Figure 3

204 tax rate areas, 24 distinct rates

San José’s 204 tax rate areas grouped by their total 2025–26 rate. The areas share 24 distinct totals. Every area pays the same 1.0732% in countywide, city and water-district levies; school and college bonds make up the rest.

  • Number of San José tax rate areas
  • Band containing the most common rate
San José's 204 tax rate areas grouped by total rate, 2025-26The 204 areas have 24 distinct total rates, from 1.1470% to 1.3161%. The most common total, 1.2079%, applies in 43 areas. Each $100,000 of ADU value adds $1,147 to $1,316 a year.0204060Tax rate areas202655825214631.14%$1,1401.16%$1,1601.18%$1,1801.20%$1,2001.22%$1,2201.24%$1,2401.26%$1,2601.28%$1,2801.30%$1,3001.32%$1,320Total tax rate (top row) and the tax it adds per $100,000 of ADU value (bottom row)Most common: 1.2079%43 areas, all in San José Unified

How to read this. Bars count tax rate areas, not homes; the county does not publish parcel counts by area in this book. Rates are for 2025–26, the latest compiled book reviewed; 2026–27 rates were not yet compiled.

Data table: the 24 distinct totals and how many areas carry each
Distinct total rate, 2025–26Tax rate areas with this totalTax per $100,000
1.1470%16$1,147
1.1562%4$1,156
1.1642%5$1,164
1.1656%2$1,166
1.1735%9$1,174
1.1784%6$1,178
1.1795%4$1,180
1.1809%1$1,181
1.1913%4$1,191
1.2030%1$1,203
1.2079%43$1,208
1.2172%11$1,217
1.2197%3$1,220
1.2246%8$1,225
1.2359%17$1,236
1.2416%4$1,242
1.2426%4$1,243
1.2487%13$1,249
1.2605%8$1,260
1.2614%22$1,261
1.2631%4$1,263
1.2645%1$1,264
1.2789%11$1,279
1.3161%3$1,316
  • 017-079 (lowest): 1.14310 + 0.00390 State Water Project = 1.1470%; schools: Morgan Hill Unified; Gavilan Joint CCD (PDF p. 112, printed p. 100).
  • 017-090 (most common): 1.20400 + 0.00390 State Water Project = 1.2079%; schools: San Jose Unified; San Jose-Evergreen CCD (PDF p. 114, printed p. 102).
  • 017-011 (highest): 1.31220 + 0.00390 State Water Project = 1.3161%; schools: Luther Burbank Elementary; Campbell Union High; West Valley-Mission CCD (PDF p. 96, printed p. 84).

County data LedgeX calc. Source: S22 (Section III, all 816 tax rate areas parsed). Extraction and chart: LedgeX Research.

The value: why your permit number is not your tax number

The assessor values new construction at its full value as of completion (Rule 463). In practice, the county says, assessors use “either the cost of construction or a market-based sales comparison” (Assessor). The job valuation on a building permit is the easiest number for an owner to find. In San José it is a poor guide to the tax.

The city’s open-data portal publishes every active building permit with its valuation and square footage. The version updated Oct. 24, 2026, lists 759 active permits with the subtype “ADU,” 749 of them for new construction (permit data). Of the 738 that report both figures, 651, or 88%, have a valuation equal, within $2, to the square footage times one of four flat rates (649 of them to the dollar): $165.67, $167.37, $169.09 or $175.92 per square foot. The city’s 2024–25 fee schedule lists $165.67 per square foot as its construction cost for one- and two-family dwellings (fee schedule). That rate accounts for 100 of the 117 permits issued that fiscal year, and each of the other rates dominates a single fiscal year. The median permit is about 632 square feet, with a median valuation of about $105,360.

So the valuation is a fee-schedule convention, not a measure of cost or value. By comparison, a UC Berkeley survey of owners who built ADUs in 2018 and 2019 found a median Bay Area cost of $329 per square foot, including design and permits (CCI survey). That is about twice the city’s table rate, and it predates several years of rising construction costs. Neither figure is what the assessor will enroll. But for the median permit, tax figured from the permit valuation ($1,273 a year) is about half of tax figured from the surveyed cost ($2,511).

LedgeX Research · Figure 4

The permit number is a fee formula

Valuation per square foot on San José’s 738 active ADU permits with both figures (file version of Oct. 24, 2026). Most sit on a handful of flat rates; owners’ reported costs sit far to the right.

  • $160–$179.99 per sq ft
  • Other valuations
  • Owner-reported median cost (survey)
San José active ADU permits by valuation per square foot651 of 738 active ADU permits are valued at square feet times one of four flat rates between $165.67 and $175.92. Bay Area owners reported a median cost of $329 per square foot for ADUs built in 2018-19.0200400600Permits$80$120$160$200$240$280$320Permit valuation per square foot530144$329/sq ftmedian cost reported byBay Area owners, 2018–19 builds651 of 738 permits= square feet × a flat rate per sq ft($165.67, $167.37, $169.09 or $175.92)

How to read this. A permit valuation is what the city uses to compute fees. The assessor enrolls market value, using construction cost or sales of comparable property. Neither the permit figure nor the survey figure is a prediction of the assessed value. Two outliers ($230s and $280s) are included in the counts.

Data table: valuation per square foot
Valuation per sq ftActive ADU permits
$80–$89.991
$90–$99.991
$100–$109.991
$110–$119.996
$120–$129.9916
$130–$139.9914
$140–$149.996
$150–$159.9913
$160–$169.99530
$170–$179.99144
$180–$189.993
$190–$199.991
$230–$239.991
$280–$289.991
Fiscal year issuedPermitsMost common $/sq ftPermits at that rate
Before 2023–2415varies—
2023-2453$167.3750 (94%)
2024-25117$165.67100 (85%)
2025-26387$169.09319 (82%)
2026-27166$175.92136 (82%)

Medians of the 738 permits: 631.5 sq ft and $105,359.50 (each the average of the two middle values). At 1.2079%, tax on the permit valuation would be $1,273 a year; on 631.5 sq ft at $329.17/sq ft, $2,511.

City data LedgeX calc. Sources: S23 S24 S28 S20. Aggregates only; no owner or address fields kept. Analysis: LedgeX Research.

When the bills arrive

Tax follows construction in two steps. On each Jan. 1 lien date, work under way is appraised at its value as it stands and goes on the next annual roll (R&T Code §71). When the work is finished, the assessor makes a supplemental assessment for the change in value. Completion is the earlier of the date the work is available for use or the date it is first used or occupied (Rule 463.500, per BOE). Cities must send the assessor a copy of every building permit and, within 30 days, any certificate of occupancy or other proof of completion (R&T Code §72), so the assessor learns of permitted work from the city.

A supplemental bill is prorated from the first day of the month after completion to June 30, the end of the fiscal year, using multipliers set in statute (R&T Code §75.41); (BOE). If the work is finished between Jan. 1 and May 31, there are two supplemental bills, one for the rest of the current year and one for the next, because the next year’s roll was set on Jan. 1, before completion (R&T Code §75.11). Supplemental bills come on top of the regular bill, not instead of it. Over a full year the pieces add up to the same amount: the ADU’s value times the rate.

LedgeX Research · Figure 5

When the bills arrive

Two hypothetical completion dates for the same $250,000 ADU. Supplemental bills are prorated from the month after completion; the regular roll catches up on the next Jan. 1.

  • Supplemental bill
  • Regular annual bill (ADU portion only)
When supplemental tax bills arrive for a finished ADUIllustration with a $250,000 ADU at 1.2079%. Finished Oct. 15, 2026: one supplemental bill of $2,023, then $3,020 a year on the regular bill. Finished Mar. 10, 2027: supplemental $755 for the rest of 2026-27; for 2027-28, the regular bill carries the in-progress value ($1,812) and a second supplemental bill adds $1,208.Jul 1, 2026Jan 1, 2027Jul 1, 2027Jan 1, 2028Jun 30, 2028lien datelien dateFiscal year 2026–27Fiscal year 2027–28A. FinishedOct. 15, 2026Supplemental $2,023Regular bill includes ADU: $3,020B. FinishedMar. 10, 2027(in progress Jan. 1)$755Regular bill, in-progress value: $1,812Second supplemental: $1,208= $3,020full yearTwo supplemental bills, because completion fell between Jan. 1 and May 31.

How to read this. Completion is treated as occurring on the first day of the next month, and the statute’s multipliers apply: 0.67 for a presumed Nov. 1 date and 0.25 for Apr. 1 (R&T Code §75.41). The rate is held at the 2025–26 figure for simplicity, and both cases assume no construction was under way on Jan. 1, 2026. The in-progress value in case B is invented. Actual bills depend on the assessor’s values and the year’s rate.

Data table: both cases
CaseBillCalculationAmount
A: finished Oct. 15, 2026Supplemental, Nov. 2026–June 2027$250,000 × 1.2079% × 0.67 (presumed Nov. 1)$2,023.23
ARegular bill from 2027–28$250,000 × 1.2079%$3,019.75
B: finished Mar. 10, 2027First supplemental, Apr.–June 2027$250,000 × 1.2079% × 0.25 (presumed Apr. 1)$754.94
BRegular bill 2027–28 (value in progress on Jan. 1)$150,000 × 1.2079%$1,811.85
BSecond supplemental, 2027–28($250,000 − $150,000) × 1.2079%$1,207.90

Illustration LedgeX calc. Sources: S3 S5 S6 S10 S11 S29. Calculation: LedgeX Research.

What doesn’t change, and what could

Renting the ADU, or the main house, doesn’t change the assessed value. One-time development fees are a separate matter from property tax: school and parkland impact fees do not apply to small ADUs. San José’s checklist, updated Sept. 16, 2026, puts the line at 750 square feet or less (Bulletin #210); the city’s fee page still says “less than 750” (city fees). Three later events can change the picture.

Selling the ADU on its own. State law lets cities adopt ordinances allowing an ADU and the main house to be sold separately as condominiums, with every lender’s written consent and a recorded condominium plan (Gov. Code §66342). San José opted in in 2024 (Ting) and in 2025 approved what was reported as the state’s first ADU condominium (PublicCEO). A sale is a change in ownership (R&T Code §60), so the unit sold is reassessed at its price. How an assessor splits a parcel’s existing value between two new condominium parcels is a question published guidance did not answer.

Selling the property. A sale of the whole parcel generally reassesses everything, including the house, the land and the ADU, at the purchase price (art. XIII A).

Solar. The Energy Code generally requires solar panels on new detached ADUs (Energy Commission). Solar systems have long been excluded from new-construction assessment, but the exclusion ends for new systems on Jan. 1, 2027 (R&T Code §73); (BOE). Systems that qualify before then keep it until the property next changes hands; a 2025 law made Jan. 1, 2027, an inoperative date rather than a repeal date, preserving that treatment (SB 710). A system finished later can be assessed like any other improvement. For an ADU finishing near year-end, the date the solar is completed now matters.

There is no state property-tax exclusion for ADUs. SB 1164 would have excluded ADUs completed from 2025 through 2029 from reassessment for 10 years, or until a sale (BOE analysis). It passed the Senate on May 22, 2024, and stalled in the Assembly when its committee hearing was canceled at the author’s request (bill history). The Assembly housing committee’s 2025 summary lists no bill on ADU assessment (Assembly), and LedgeX found no ADU exclusion enacted in 2025 or 2026. A guide that describes an ADU tax break as current is out of date.

Checking the assessor’s number

An owner who thinks a new-construction value is wrong has two routes in Santa Clara County. The Assessor’s staff will review factual issues informally, and the county asks owners to call within 30 days of receiving an annual, supplemental or corrected notice (Assessor). A formal appeal of a supplemental assessment must be filed with the Clerk of the Board within 60 days of the date of the notice; appeals of the regular annual value are filed from July 2 to Sept. 15 (appeals). Because cost is one of the two measures the county says it uses, final construction invoices are useful evidence to keep.

What this article does not establish

It does not estimate the value the assessor will enroll for any ADU, and no public record lets anyone do that in advance. The rate analysis counts tax rate areas, not homes, so it does not show what share of San José parcels pays each rate. It uses 2025–26 rates; 2026–27 rates were not yet compiled in the county book when this was written. It covers ad valorem taxes only. Flat parcel taxes, Mello-Roos special taxes and other charges on a bill are not in these rates. It does not cover transfers to children, which follow Proposition 19’s separate rules.

The permit analysis rests on one day’s file of active permits; finaled permits are not in it. The match between valuations and city table rates is exact for $165.67, which appears in the 2024–25 fee schedule. The other three rates are inferred from the permits themselves.

LedgeX Research ties each figure to its source and labels it statute, county data, city data, illustration or calculation. LedgeX’s product, in private testing for San José single-family properties, applies the same rule to parcel facts. It does not estimate property taxes. For what state law allows on a lot, see ADUs 101 and San José ADU requirements.

About the data and graphics

  • Tax rates. All 816 tax rate area blocks in Section III of the county’s 2025–26 rate book were parsed. For each area, the total is the net-value subtotal plus the Santa Clara Valley Water District State Water Project levy, which the book applies to land and improvements. Figure 3’s data table lists the 24 distinct San José totals, how many of the 204 areas carry each, and three worked examples with page numbers. A second, independent parse summed every line item without using the book’s subtotals and reproduced all 204 totals; the three example pages were also checked by eye S22.
  • Permits. The city’s Active Building Permits file (version last modified Oct. 24, 2026) was filtered to the subtype “ADU”; no permit outside that subtype mentions an ADU in its work description. Only aggregates were kept. Valuation per square foot was computed for the 738 permits reporting both figures, and a permit was counted as a table-rate permit if its valuation was within $2 of square footage times $165.67, $167.37, $169.09 or $175.92 (649 match to the dollar; 653 within $5.50). The counts were reproduced with a second, independently written parser S23 S24.
  • Illustrations. Figures 1 and 5 use invented values to show how the rules work, not to estimate any bill. Proration multipliers are those in R&T Code §75.41(c), cross-checked against a county assessor’s published table S6 S29.
  • Calculations. Every computed figure is generated by the build script and checked; each can be reproduced from the figures’ data tables.
  • City guidance. San José’s ADU FAQ says taxes “will increase based on the value of the ADU” and refers owners to the Assessor S25. The ADU checklist, Bulletin #210 (updated Sept. 16, 2026, the edition the city’s checklist page serves), does not address property tax S26.
  • Legal questions. This article describes statutes and agency guidance. It is not legal or tax advice, and an assessor decides each property’s value.
  • Currency. Records as published through Oct. 24, 2026

Sources

  1. S1 California Constitution, article XIII A, §2 (Proposition 13: base year values, new construction, 2% cap) — California Legislature, current. Constitution. https://leginfo.legislature.ca.gov/faces/codes_displayText.xhtml?lawCode=CONS&article=XIII%20A
  2. S2 Revenue and Taxation Code §70 (definition of new construction) — California Legislature, current. Statute. https://leginfo.legislature.ca.gov/faces/codes_displaySection.xhtml?lawCode=RTC&sectionNum=70.
  3. S3 Revenue and Taxation Code §71 (base year for the new portion; construction in progress on the lien date) — California Legislature, current. Statute. https://leginfo.legislature.ca.gov/faces/codes_displaySection.xhtml?lawCode=RTC&sectionNum=71.
  4. S4 Revenue and Taxation Code §72 (permits and completion documents sent to the assessor) — California Legislature, current. Statute. https://leginfo.legislature.ca.gov/faces/codes_displaySection.xhtml?lawCode=RTC&sectionNum=72.
  5. S5 Revenue and Taxation Code §75.11 (one or two supplemental assessments) — California Legislature, current. Statute. https://leginfo.legislature.ca.gov/faces/codes_displaySection.xhtml?lawCode=RTC&sectionNum=75.11.
  6. S6 Revenue and Taxation Code §75.41 (proration of supplemental assessments; multipliers by presumed date in subd. (c)) — California Legislature, current. Statute. https://leginfo.legislature.ca.gov/faces/codes_displaySection.xhtml?lawCode=RTC&sectionNum=75.41.
  7. S7 Revenue and Taxation Code §60 (definition of change in ownership) — California Legislature, current. Statute. https://leginfo.legislature.ca.gov/faces/codes_displaySection.xhtml?lawCode=RTC&sectionNum=60.
  8. S8 Revenue and Taxation Code §73 (active solar energy system exclusion) — California Legislature, current. Statute. https://leginfo.legislature.ca.gov/faces/codes_displaySection.xhtml?lawCode=RTC&sectionNum=73.
  9. S9 Property Tax Rule 463, Newly Constructed Property (last amended 1998) — State Board of Equalization, 1998-06-12. Regulation. https://www.boe.ca.gov/proptaxes/pdf/rules/Rule463.pdf
  10. S10 Supplemental Assessment (program page) — State Board of Equalization, current. Primary (state). https://boe.ca.gov/proptaxes/supplemental-assessment
  11. S11 Legislative bill analysis, SB 1164 (Newman), as amended May 16, 2024; describes existing law and Rule 463.500 — State Board of Equalization, 2024. Primary (state). https://www.boe.ca.gov/legdiv/pdf/1164sb051624rd.pdf
  12. S12 SB 1164 (2023–24): bill history (passed Senate May 22, 2024; Assembly hearing June 24, 2024 canceled at author’s request) — California Legislature, 2024. Legislative record. https://leginfo.legislature.ca.gov/faces/billHistoryClient.xhtml?bill_id=202320240SB1164
  13. S13 2025 Legislative Bill Summary — Assembly Committee on Housing and Community Development, 2025-12. Primary (state). https://ahcd.assembly.ca.gov/system/files/2025-12/2025-legislative-bill-summary_final.pdf
  14. S14 Letter To Assessors No. 2024/031: section 73 solar exclusion sunset — State Board of Equalization, 2024. Primary (state). https://www.boe.ca.gov/proptaxes/pdf/lta24031.pdf
  15. S15 SB 710 (Blakespear), Stats. 2025, ch. 328: solar exclusion continues until a change in ownership — California Legislature, 2025-10-03. Statute. https://leginfo.legislature.ca.gov/faces/billNavClient.xhtml?bill_id=202520260SB710
  16. S16 Energy Code Support Center: General Information on ADUs (2025 Energy Code) — California Energy Commission, current. Primary (state). https://www.energy.ca.gov/programs-and-topics/programs/building-energy-efficiency-standards/energy-code-support-center-6/2025
  17. S17 Government Code §66342 (local ordinances allowing ADUs to be sold as condominiums; AB 1033’s provision, recodified by SB 477, Stats. 2024, ch. 7) — California Legislature, current. Statute. https://leginfo.legislature.ca.gov/faces/codes_displaySection.xhtml?lawCode=GOV&sectionNum=66342.
  18. S18 San José homeowners can now sell their accessory dwelling unit (press release) — Office of Assemblymember Phil Ting, 2024-07-19. Reported (official release). https://a19.asmdc.org/press-releases/20240719-san-jose-homeowners-can-now-sell-their-accessory-dwelling-unit-because-new
  19. S19 San José approves the first ADU condominium in California — PublicCEO, 2025-08-18. Reported. https://www.publicceo.com/2025/08/san-jose-approves-the-first-adu-condominium-in-california/
  20. S20 Granny Units/Accessory Dwelling Units — Santa Clara County Assessor, current. Primary (county). https://www.sccassessor.org/property-information/homeowners/granny-units-accessory-dwelling-units
  21. S21 Contesting Your Assessed Value — Santa Clara County Assessor, current. Primary (county). https://www.sccassessor.org/property-information/homeowners/disputing-your-assessed-value
  22. S22 Compilation of Tax Rates & Information, Fiscal Year 2025–2026 — County of Santa Clara, Department of Finance, 2025-11. Primary (county). https://files.santaclaracounty.gov/exjcpb1531/2025-11/tax-rate-book-2025-2026.pdf
  23. S23 Active Building Permits (open dataset; updated daily; version last modified Oct. 24, 2026) — City of San José, 2026-10-24. Primary (city data). https://data.sanjoseca.gov/dataset/active-building-permits
  24. S24 FY 2024-25 Building Division Fee Schedule (ICC group square-foot construction costs) — City of San José, 2024-08-12. Primary (city). https://sanjoseca.gov/home/showpublisheddocument/26047/638598545783230000
  25. S25 ADU FAQs — City of San José, current. Primary (city). https://sanjoseca.gov/business/development-services-permit-center/accessory-dwelling-units-adus/adu-faqs
  26. S26 Bulletin #210, ADU Universal Checklist (updated Sept. 16, 2026) — City of San José Building Division, 2026-09-16. Primary (city). https://www.sanjoseca.gov/businesses/development-services-permit-center/accessory-dwelling-units-adus/adu-universal-checklist
  27. S27 Fees for ADUs — City of San José, current. Primary (city). https://www.sanjoseca.gov/business/development-services-permit-center/accessory-dwelling-units-adus/fees
  28. S28 Implementing the Backyard Revolution: Perspectives of California’s ADU Owners — UC Berkeley Center for Community Innovation, 2021. Survey (academic). https://www.urbandisplacement.org/wp-content/uploads/2021/09/Implementing-the-Backyard-Revolution.pdf
  29. S29 A Guide to the Supplemental Assessment Process (monthly proration factors; cross-check of §75.41) — Sacramento County Assessor, current. Primary (county; statewide factors). https://assessor.saccounty.gov/content/assessor/us/en/frequently-asked-questions/guide-to-supplemental-assessment-process.html

About this research: LedgeX Research examines the public records, physical constraints and economic forces that shape land and property decisions. We separate findings from hypotheses and unresolved questions. This article is not tax, legal or investment advice. Corrections: team@ledgexproperties.com.