California Code, Health and Safety Code - HSC § 32240

Whenever it is desired that expenditures be made by the district for the acquisition, construction, maintenance, or alteration of work for the purpose of facilitating the carrying out of the purpose of this division in any district, the board of directors thereof may submit to the electors of the district the question of whether or not the additional expenditure shall be made out of the proceeds of a special assessment to be levied in like manner and on the same basis as the regular annual assessment made by the district.