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Real Property


The value enrolled at the time the property is acquired (or the 1975 value if acquired before 1975) is called the property's base year value. This value is annually increased by a factor of no more than 2% and is based on the prior year's Consumer Price Index. The base year value factored is referred to as the Proposition 13 value. The base year value changes only when there is a change in ownership or new construction to the property.


New Construction

Building permits are sent to the Assessor from all cities and the county. This is the primary method of discovering new construction in the county. An appraisal determines the value the new construction adds to the property as of the date of completion, and that value is then added to the existing property value. This usually results in a Supplemental Assessment. Normal repairs, replacement or maintenance are typically not considered new construction. This may consist of replacing a roof, replacing kitchen appliances, or replacing plumbing fixtures.


Major renovation or rehabilitation of a structure, which makes it substantially the equivalent of new construction or changes the use of the property, is also considered new construction. That value added by the new construction or change in use is added to the property's value as of the date of completion. This usually results in a Supplemental Assessment.


If the new construction is incomplete on lien date (January 1), a partial value reflecting what was there at that time will be added for the upcoming tax year.


Supplemental Assessment

A supplemental tax bill is issued in addition to the annual tax bill and is based on the difference between the new assessed value for the property and the assessed value before the change in ownership or completion of new construction. The bill covers the period from the change date to the end of the fiscal year (June 30). If the change takes place between January 1 and May 31, there will be 2 supplemental tax bills. The second one will be for the following fiscal year. After that, the regular tax bill should reflect the new value. (Note: supplemental tax bills are usually not paid by impound accounts.)


Builder's Exclusion

New construction built for resale may be excluded from supplemental assessment under certain conditions. The builder must file the necessary form with the Assessor's Office prior to or within 30 days of the start of construction. For more information, call (209) 468-2658. Click here for form.


Declines In Value

State law provides that when the current market value is less than the Proposition 13 value (value at the time of acquisition plus annual inflation factor not exceeding 2%), the market value is to be enrolled for that tax year. These properties are then reviewed annually and the current market value continues to be enrolled until that value is greater than the Proposition 13 value. During this time, the annual property value may increase more than 2% per year until the Proposition 13 value is restored.


Williamson Act (Land Conservation Act)

Agricultural landowners who sign a contract with the County placing their land in the Williamson Act will have their agricultural land and living improvements valued according to a special form of income capitalization. The value is generally lower than the Proposition 13 value and these values are recalculated annually. Homesites, non-living improvements and outbuildings are valued on the same basis as other property under Proposition 13.


Manufactured Housing

Manufactured housing sold new on or after July 1, 1980 is subject to property taxation. Many mobile homes first sold before this date are not taxed by the county, but instead are registered annually and licensed with the State Department of Housing & Community Development (HCD). All mobile homes placed upon permanent foundations are subject to property taxation regardless of the date first sold. Owners of manufactured housing subject to property taxation are eligible to the same exemptions and exclusions as real property owners.


Contesting Assessed Values

If you disagree with your assessed value, you should first contact the Assessor's office to request a review of the value. If the matter is not resolved to your satisfaction, you may then file an appeal with the Assessment Appeals Board. Appeals for the regular roll must be filed July 2 through November 30. Appeals to the supplemental roll must be filed within 60 days of the supplemental notice date.


To file an appeal, you will need to contact the Clerk of the Board at (209) 468-2350 to request appeal forms and instructions.






Assessor's Office

44 North San Joaquin Street
Second Floor Suite 230
Stockton, CA 95202
Phone: (209) 468-2630
Fax: (209) 468-8383
Office Hours: 8:30 - 4: 30