Wat. Code, § 60604

(a) For any improvement or unit of work done by district personnel, the estimated cost of the work shall not exceed twenty-five thousand dollars ($25,000), except under either of the following circumstances:

(1) The work consists of maintenance work, as defined in subdivision (d) of Section 22002 of the Public Contract Code.

(2) The work consists of emergency work.

(b) Notice of a contract for any improvement or work shall be made by the district after publication pursuant to Section 6064 of the Government Code. The notice shall set forth all of the following information:

(1) Plans and specifications of the work to be done can be seen at the office of the district.

(2) The board will receive sealed bids.

(3) The contract will be let to the lowest responsible bidder.

(4) The bids will be opened in public at a given time and place.

(c) If less than the whole work provided for in the plans and specifications is to be done, the portion to be done shall be particularly described in the notice.

(d) 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) Cash.

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

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

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

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

(f) The board may do any of the following:

(1) Let the work to the lowest responsible bidder.

(2) Reject any or all bids and readvertise for proposals.

(3) Proceed to construct the work under its own superintendence.

(4) If no bids are received, negotiate a contract for the work.