CA Water Code Section 26000

A board shall order the collector to cancel or modify, as may be proper, an assessment when it finds that any property has been either:

(a)

Assessed in any year more than once.

(b)

Assessed by reason of a clerical error for more than its full cash value.

(c)

Computed for assessment on an excessive acreage.

(d)

Assessed while not in the district.