Streets and Highways Code § 11804

The legislative body may levy and collect in any year upon and against all of the taxable land and improvements within the district a special ad valorem assessment sufficient to raise a sum of money not exceeding the net amount determined pursuant to Section 11803 but the rate of assessment in any one year shall not exceed fifty cents ($0.50) on each one hundred dollars ($100) assessed value as shown on the assessment roll used by the city for city taxation.