Proposition 13 Explained: California’s Property Tax System Made Simple

If you’ve ever wondered why two nearly identical California homes can have dramatically different property tax bills, the answer is usually Proposition 13.

Approved by California voters in 1978, Proposition 13 fundamentally changed how property taxes are calculated. More than four decades later, it continues to shape the tax bills of nearly every California homeowner.

Understanding Proposition 13 is essential whether you’re buying your first home, planning to move, or simply trying to understand your annual property tax bill.

What Is Proposition 13?

Proposition 13 is an amendment to the California Constitution approved by voters in June 1978.

Before Proposition 13, rapidly increasing home prices caused property taxes to rise dramatically each year. Many homeowners – particularly retirees living on fixed incomes – found themselves struggling to keep up with escalating tax bills.

Proposition 13 introduced two major changes:

• It generally limits the basic property tax rate to 1% of assessed value.
• It limits annual increases in assessed value to no more than 2% per year unless the property changes ownership or undergoes new construction.

These two protections remain the foundation of California’s property tax system today.

How Proposition 13 Works

When you purchase a home, the purchase price usually becomes your property’s base year value.

Each year afterward, your county assessor may increase that assessed value by up to 2%, regardless of how much the home’s market value actually increases.

If that same home is now worth $1.4 million, property taxes are still generally calculated using the Proposition 13 assessed value – not today’s market value.

Why Proposition 13 Matters

California has experienced some of the fastest home price appreciation in the United States.

Without Proposition 13, many homeowners would see property taxes increase alongside market values every year.

Instead, long-term homeowners often pay substantially less in property taxes than recent buyers of similar homes.

An Example

Imagine two neighbors with identical homes worth $1.5 million today.

What Happens When You Buy a Home?

One of the most important features of Proposition 13 is that property taxes usually reset when ownership changes.

For most home purchases:

• The purchase price becomes the new base year value.
• Future increases are again limited to 2% annually.

This is why buyers often notice a substantial increase in property taxes compared with the previous owner’s bill.

What Happens If Home Values Fall?

Proposition 13 also works together with another law known as Proposition 8.

If your home’s market value temporarily falls below its Proposition 13 assessed value, your county assessor may reduce your taxable value.

When the market recovers, your assessed value can increase again – but only until it reaches the Proposition 13 limit.

Does Proposition 13 Prevent All Property Tax Increases?

No.

While Proposition 13 limits assessed value growth, your total tax bill may still increase because of:

• Local bond measures
• Mello-Roos taxes
• Community Facilities District (CFD) assessments
• Parcel taxes
• Special assessments
• New construction or major improvements

These charges are separate from Proposition 13’s assessment limits.

Homeowners’ Exemption

Many California homeowners also qualify for the state’s $7,000 Homeowners’ Exemption, which reduces taxable assessed value slightly for owner-occupied primary residences.

Although the savings are relatively small, most eligible homeowners should apply.