One of the most common mistakes homeowners in California make is assuming property tax deadlines work like federal income taxes, with extensions or wiggle room. In reality, California property tax rules are rigid. A missed deadline can instantly trigger steep penalties, and long-term delinquency can even lead to property loss through a tax sale.

The good news is that the property tax calendar is predictable once you understand it. Here is a breakdown of the important dates you cannot afford to overlook.

The California Property Tax Timeline

California’s property tax system follows the state’s fiscal year, running July 1 through June 30. Here are the major milestones:

• January 1 – Lien Date: Property is assessed based on ownership and value as of this date. Whoever owns the property on January 1 is responsible for the upcoming fiscal year’s taxes.

• July 1 – Beginning of the fiscal year. Unpaid property taxes from the prior year are officially in default.

• October – Annual property tax bills are mailed out by county tax collectors. If you do not receive your bill by late October, it is your responsibility to contact the county.

Installments and Delinquent Dates

• First Installment:

  • Due November 1

  • Delinquent after December 10

  • If not paid by December 10, a 10% penalty is immediately applied.

• Second Installment:

  • Due February 1

  • Delinquent after April 10

  • If not paid by April 10, a 10% penalty applies plus a $10 administrative fee.

June 30 – End of the fiscal year. Any taxes unpaid by this date are declared tax defaulted, and the property enters delinquent status with a 1.5% monthly penalty (18% annually) until paid. After five years of delinquency, the county can auction the property to recover the debt.

Supplemental Property Tax Deadlines

When a property changes ownership or new construction occurs, California issues supplemental property tax bills in addition to the regular annual bill. Deadlines are:

• If mailed July 1 – October 30: First installment due January 31, delinquent February 1.

• If mailed November 1 – June 30: First installment due the last day of the month after the bill is mailed, delinquent the following day.

These bills often catch new homeowners off guard since escrow accounts may not cover them.

Unsecured Property Tax Deadlines

Unsecured property taxes (for business property, boats, and aircraft) follow a slightly different timeline:

• Bill Mailed: Typically in July.

• Payment Due: August 31.

• Delinquent: If not paid by September 1, a 10% penalty is applied plus collection fees.

Best Practices to Stay Compliant

• Mark your calendar: Record November 1, December 10, February 1, April 10, and June 30 as annual reminders.

• Plan for supplemental bills: If you just bought or remodeled a home, budget for an additional bill within months of closing.

• Confirm escrow coverage: Lenders often pay taxes through escrow, but mistakes happen. Verify payments were posted.

• Avoid last-minute payments: If mailing a check, ensure the postmark is on or before the delinquent date. Online systems can also get overloaded close to deadlines.

• Keep records: Save payment confirmations or check images to resolve any disputes with the county.