All bids for construction work shall be presented under sealed cover and shall be accompanied by one of the following forms of bidder’s security:

(a) Cash.

(b) A cashier’s check made payable to the district.

(c) A certified check made payable to the district.

(d) A bidder’s bond executed by an admitted surety insurer, made payable to the district.

Upon an award to the lowest bidder, the security of an unsuccessful bidder shall be returned in a reasonable period of time, but in no event shall that security be held by the district beyond 60 days from the time the award is made.

(Amended by Stats. 1990, Ch. 808, Sec. 8.)