California Proposition 8 Explained
Most California homeowners understand Proposition 13, but far fewer know about Proposition 8.
While Proposition 13 generally limits annual increases in assessed value, Proposition 8 allows a county assessor to temporarily reduce a property's taxable value when its market value falls below its normal Proposition 13 factored base-year value.
Understanding Proposition 8 helps explain why property taxes sometimes decrease during housing downturns and why assessments can later increase by more than 2% without violating Proposition 13.
New to this topic? Start with Proposition 13 Explained.
What Is Proposition 8?
Proposition 8 is a California constitutional amendment approved by voters in 1978, alongside Proposition 13.
For property tax purposes, Proposition 8 established the principle that when a property's current market value falls below its normal Proposition 13 factored base-year value, the county assessor may temporarily enroll the lower market value for taxation.
This prevents property owners from paying taxes on an assessed value that exceeds the property's current market value. Unlike Proposition 13, Proposition 8 reductions are temporary.
The Basic Concept
Every California property effectively has two important values. The county generally enrolls whichever value is lower.
1. Proposition 13 factored base-year value
The property's normal assessed value after applying the annual Proposition 13 inflation adjustments. It generally represents the highest assessed value that can be reached without another reassessment event.
2. Current market value
The property's estimated fair market value today. When it falls below the Proposition 13 factored base-year value, the assessor may temporarily assess the property at this lower value under Proposition 8.
Example
During a housing downturn, the county may enroll the lower current market value instead of the higher Proposition 13 value:
Proposition 8 in a downturn
- Purchase price
- $700,000
- Factored base-year value (normal Prop 13)
- $820,000
- Current market value
- $690,000
- Temporarily enrolled taxable value
- $690,000
The homeowner benefits from paying taxes on the lower value.
What Happens When the Market Recovers?
Suppose the next year the property's market value rises to $760,000. The county may increase the taxable value from $690,000 to $760,000 — an increase of about 10%.
This does not violate Proposition 13.
The increase is permitted because the property is simply returning toward its normal Proposition 13 factored base-year value.
When a property has received a temporary Proposition 8 reduction, the county may restore the taxable value by more than 2% in a single year as market values recover. The taxable value generally cannot exceed the property's current Proposition 13 factored base-year value unless another reassessment event occurs.
Why Assessments Can Increase More Than 2%
One of the biggest misconceptions about California property taxes is that assessed values can never increase by more than 2%. That is only generally true while the property is following its normal Proposition 13 assessment path. A property recovering from a Proposition 8 reduction can rise faster, up to its normal Proposition 13 factored base-year value.
How Counties Determine Proposition 8 Values
Proposition 8 reductions are not automatic. Each county assessor determines whether a property's market value has fallen below its Proposition 13 value. Assessors commonly use:
- recent comparable sales,
- appraisal techniques,
- neighborhood market trends,
- property characteristics,
- and other valuation methods.
Some counties review large numbers of properties using mass appraisal techniques, but the enrolled value is still determined on a parcel-by-parcel basis.
How Long Does a Proposition 8 Reduction Last?
A Proposition 8 reduction remains only while the property's market value is below its normal Proposition 13 factored base-year value. Each year the assessor reviews whether the reduced value should:
- remain the same,
- increase,
- decrease further,
- or return to the normal Proposition 13 value.
Once market value equals or exceeds the Proposition 13 factored base-year value, the temporary reduction ends.
How Proposition 8 Differs from Proposition 13
| Proposition 13 | Proposition 8 |
|---|---|
| Establishes the property's base-year value | Allows temporary reductions when market value falls |
| Generally limits annual inflation adjustments | Allows temporary market-value assessments |
| Creates the normal assessment path | Creates temporary exceptions during market declines |
| Continues indefinitely | Ends when market value recovers |
Common Misconceptions
“Property taxes can never decrease.”
Incorrect. If market value declines sufficiently, Proposition 8 allows a temporary reduction in assessed value.
“Property taxes can never increase by more than 2%.”
Incorrect. A Proposition 8 property may experience increases greater than 2% while returning toward its normal Proposition 13 value.
“The county permanently lowered my assessed value.”
Usually not. Most Proposition 8 reductions are temporary. As the market recovers, the county may restore the property's taxable value.
Decline-in-value & disaster relief by county
Proposition 8 relief is not rare. In 2025, California county assessors granted 413,054 decline-in-value reductions statewide across 48 counties (down from 418,073 the year before). Separately, assessors reassessed 23,124 properties for misfortune or calamity in 2025 — overwhelmingly in Los Angeles County (18,328), reflecting that year's wildfires and disasters.
Showing 48 of 48 counties.
| County (2025) | ||
|---|---|---|
| Riverside | 63,570 | 4,814 |
| Orange | 43,564 | 1,541 |
| Kern | 32,541 | 5,713 |
| San Diego | 31,159 | 5,722 |
| El Dorado | 23,483 | 5,247 |
| San Bernardino | 20,184 | 8,761 |
| Placer | 18,120 | 11,540 |
| Contra Costa | 15,280 | 12,906 |
| Modoc | 12,323 | 173 |
| Sacramento | 11,506 | 9,815 |
| Los Angeles | 11,467 | 3,623 |
| San Francisco | 11,146 | 7,523 |
| San Luis Obispo | 9,046 | 172 |
| Santa Clara | 8,701 | 8,116 |
| Ventura | 8,526 | 1,560 |
| San Joaquin | 8,354 | 7,314 |
| Alameda | 8,180 | 7,936 |
| Nevada | 6,988 | 6,068 |
| San Mateo | 6,581 | 5,627 |
| Fresno | 5,840 | 4,518 |
| Butte | 5,368 | 1,351 |
| Stanislaus | 5,064 | 3,713 |
| Shasta | 4,201 | 2,511 |
| Calaveras | 3,766 | 2,017 |
| Solano | 3,749 | 3,100 |
| Siskiyou | 3,693 | 3,220 |
| Tehama | 3,424 | 3,030 |
| Merced | 3,055 | 2,437 |
| Napa | 2,513 | 480 |
| Monterey | 2,369 | 1,140 |
| Tuolumne | 2,288 | 1,418 |
| Madera | 2,185 | 1,119 |
| Mono | 2,115 | 61 |
| Sonoma | 1,873 | 1,632 |
| Tulare | 1,856 | 1,439 |
| Yolo | 1,684 | 1,442 |
| Humboldt | 1,581 | 613 |
| Amador | 1,255 | 1,173 |
| Yuba | 1,050 | 734 |
| Sutter | 908 | 130 |
| San Benito | 463 | 328 |
| Inyo | 426 | 35 |
| Mariposa | 416 | 416 |
| Colusa | 384 | 293 |
| Santa Cruz | 308 | 148 |
| Del Norte | 191 | 42 |
| Kings | 161 | 110 |
| Sierra | 149 | 103 |
Disaster (calamity) reassessments, 2025
If a disaster damages your property, California lets the assessor temporarily lower its value (Revenue & Taxation Code §170) — separate from a Proposition 8 market decline. The counties with the most calamity reassessments in 2025 were Los Angeles 18,328, El Dorado 1,318, Fresno 589, Ventura 510. File a calamity claim with your county assessor, usually within 12 months of the damage.
Source: California State Board of Equalization — assessors' workload tables (decline-in-value, calamity, assessment appeals). Counts are reductions/reassessments processed in the year shown and can lag the event; confirm with your county assessor.
Frequently Asked Questions
Does every property qualify for Proposition 8?
No. The assessor must determine that the property's current market value is below its Proposition 13 factored base-year value.
Do I need to apply?
Practices vary by county. Some assessors automatically review properties for possible Proposition 8 reductions, while property owners may also have the ability to request review or appeal assessments according to county procedures.
Does Proposition 8 create a new base-year value?
No. The original Proposition 13 base-year value remains in place. Proposition 8 simply allows the county to temporarily enroll a lower taxable value.
Will my taxes automatically increase when the market improves?
They may. If the property's market value rises, the county may increase the taxable value toward the Proposition 13 factored base-year value.
Can the county raise my assessment above the Proposition 13 value?
Generally no, unless another reassessment event such as a change in ownership or taxable new construction occurs.
How common are Proposition 8 reductions in California?
Very common in down markets. In 2025, county assessors granted about 413,054 decline-in-value reductions statewide across 48 counties — led by Riverside, Orange, and Kern County. The by-county table above shows how many each county granted, including the single-family share.
What if my home is damaged in a fire or disaster?
That is handled through calamity (misfortune) reassessment under Revenue & Taxation Code §170, which is separate from a Proposition 8 market decline. Assessors reassessed about 23,124 properties for misfortune or calamity in 2025, most in Los Angeles County. File a calamity claim with your county assessor, generally within 12 months of the damage.
How Our Calculator Handles Proposition 8
The California Property Tax Calculator estimates a property's normal Proposition 13 assessment path using:
- purchase price,
- purchase year,
- official historical inflation factors,
- county-level estimated tax rates.
Version 1 does not attempt to estimate temporary Proposition 8 reductions because they depend on parcel-specific market value determinations made by the county assessor. For that reason, the calculator estimates the property's Proposition 13 factored base-year value, not the county's current enrolled taxable value.
Primary sources: Revenue and Taxation Code §51 (decline in value) · Revenue and Taxation Code §170 (disaster relief) · Revenue and Taxation Code §1603 (assessment appeal) · California State Board of Equalization, assessors' workload tables. Check a figure against the document before relying on it. Last reviewed October 2026.
Learn More
This guide is provided for educational purposes only and summarizes general California property tax concepts. Proposition 8 determinations are made by county assessors based on individual property valuations and applicable California law. Property owners should consult their county assessor or a qualified professional regarding specific assessment questions.