Property tax assessment in California begins with understanding that the county assessor is the official responsible for placing a value on your property each year. The assessor does not set your tax rate; instead, the assessed value is multiplied by the tax rate, which is typically about one percent of the assessed value plus voter-approved bonds and special assessments. Your first practical step is to identify your county assessor’s office, since California is a county-based system and each of the fifty-eight counties runs its own assessment operation. You can find the office through your county government website or by calling the county main line.

The next step is to locate your Assessor Parcel Number, commonly called the APN. This number is a unique identifier assigned to every parcel of land in the county. It typically appears on your property tax bill, your recorded deed, and any title documents you received when you purchased the property. The APN is usually formatted as a series of digits separated by dashes, such as 123-456-789, though formats vary by county. If you cannot find it, you can search your county assessor’s online parcel viewer using your street address or the owner’s name.

Once you have the APN, use it to look up your property’s assessment record. Most county assessors offer an online portal where you enter the APN and see the assessed value, the land and improvement values separately, the property characteristics, and the most recent transfer date. This record is the foundation for checking whether your assessment is accurate. Verify that the square footage, bedroom and bathroom count, lot size, and year built match what you know about the property, because errors in these details can inflate your value.

The third step is to understand how your value was set. Under Proposition 13, the assessed value is generally the purchase price at the time of the last change in ownership, increased by no more than two percent per year, plus any new construction. If you bought the home recently, your base year value should closely match your purchase price. If you have owned it for many years, the value should reflect the capped annual increases. Compare the assessed value on the record with your own calculation to see whether the numbers make sense.

The fourth step is to review your annual property tax bill, which usually arrives in the fall and covers the fiscal year from July first through June thirtieth. The bill shows the assessed value, the tax rate, and the breakdown of charges. Check that the APN on the bill matches your records and that the assessed value is consistent with the assessor’s parcel record. Discrepancies between the bill and the record are worth resolving early.

The fifth step, if you believe the value is too high, is to file an assessment appeal. California requires appeals to be filed with the county assessment appeals board, not the assessor, and the deadline is generally either September fifteenth or the date shown on your tax bill, whichever is later, though some counties use different windows. You must file by the deadline for the year you are contesting. Prepare evidence such as recent comparable sales, an independent appraisal, or documentation of property defects, and attend the hearing if one is scheduled.

The final step is to keep your records organized and monitor changes. Save your deed, tax bills, appeal filings, and any correspondence with the assessor. Watch for notices of supplemental assessment after new construction or a change in ownership, since these can raise your bill. If you disagree with a supplemental assessment, you have the right to appeal that as well. By tracking your APN and reviewing your assessment each year, you can catch errors early and keep your property tax burden accurate.

For more on this, see parcel records guide.