(a) Except as provided by Subsection (b) of this section, Subchapter I, Chapter 49, Water Code, applies to a district contract for construction work, equipment, materials, or machinery.
(b) The board may adopt rules governing receipt of bids and the award of the contract and providing for the waiver of the competitive bid requirement if:
(1) there is an emergency;
(2) the needed materials are available from only one source;
(3) in a procurement requiring design by the supplier competitive bidding would not be appropriate and competitive negotiation, with proposals solicited from an adequate number of qualified sources, would permit reasonable competition consistent with the nature and requirements of the procurement; or
(4) after solicitation, it is ascertained that there will be only one bidder.