Real Property Assessment

The Assessor Division compiles a roll of property tax assessments for delivery to the County Controller by July 1 each year. This “Local Assessment Roll” covers more than 237,000 assessments countywide, value in excess of $206 billion.

A copy of the Local Assessment Roll is available at the Assessor Division front counter for public inspection. The Assessor Division also reassesses personal property each year.

Real Property

Real property is fixed property, principally land and buildings. Under Proposition 13, real property is reappraised when a change in ownership occurs or when new construction takes place. Except under special situations, real property assessments may not be increased by more than 2% annually, unless there is a change in ownership or new construction.

Mobile Homes

A mobile home is a structure that is transportable, used with or without a foundation, and designed and equipped to contain no more than two dwelling units. All mobile homes purchased new after June 30, 1980 and those on permanent foundations are subject to property taxes. As with real property, the assessed value of mobile homes may not be increased by more than 2% annually, unless there is a change in ownership or new construction.

Proposition 13

The assessment process in California was substantially modified in 1978 by California Constitution Article XIII A, also known as Proposition 13. Proposition 13 established base year assessment values, limited annual real property assessment increases to no more than 2 percent, and limited property taxes to 1% of a property’s assessed value.

• Proposition 13 allows real property to be reappraised if:
• A change in ownership occurs; or
• New construction is completed; or
• New construction is unfinished on January 1st (also known as the “lien date”); or
• It is part of an annual review of properties having declining value; or
• It is part of land conservation contract (Williamson Act)

Supplemental Assessments

When the Assessor reappraises real property due to a change in ownership or completion of new construction, the additional assessment is called a “supplemental assessment” and reflects the difference between the current roll value and the new value. The supplemental assessment generates a supplemental tax bill pro-rated for the number of months remaining in the fiscal year, which runs from July 1 through June 30. This assessment is in addition to the regular tax bill or refund.

Some events create two supplemental assessments. Events occurring January through May, known as the “window period,” affect two fiscal years and require two supplemental assessments. This is because the current tax year, which ends June 30, has not yet ended, and the next tax year’s values were set as of January 1, so both rolls are affected.