(a)

1. (1) The governing board of any school district, in accordance with any requirement established by that governing board pursuant to subdivision (a) of Section 2000, shall let any contracts involving an expenditure of more than fifty thousand dollars ($50,000) for any of the following:

   1. (A) The purchase of equipment, materials, or supplies to be furnished, sold, or leased to the district.
   2. (B) Services, except construction services.
   3. (C) Repairs, including maintenance as defined in Section 20115, that are not a public project as defined in subdivision (c) of Section 22002.
2. (2) The governing board shall let the contract to the lowest responsible bidder who shall give security as the board requires, or else reject all bids.

(b)

1. (1) The governing board shall let any contract for a public project, as defined in subdivision (c) of Section 22002, involving an expenditure of fifteen thousand dollars ($15,000) or more, to the lowest responsible bidder who shall give security as the board requires, or else reject all bids. 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:

   1. (A) Cash.
   2. (B) A cashier’s check made payable to the school district.
   3. (C) A certified check made payable to the school district.
   4. (D) A bidder’s bond executed by an admitted surety insurer, made payable to the school district.
2. (2) Upon 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 school district beyond 60 days from the time the award is made.