The Commission shall provide an opportunity for a hearing before proceeding with the design or construction of a water supply or sanitary sewer system. Subject to subsection (c) of this section, the Commission: shall advertise in newspapers and technical media that the Commission considers appropriate for bids or proposals for design or construction services for any part of a water supply or sanitary sewer system; and may readvertise any part of the services needed if the Commission considers the prices quoted in response to a prior advertisement to be unreasonable. Subject to paragraph (2) of this subsection, the Commission may use day labor to complete any part of the design or construction of a water supply or sanitary sewer system. Notwithstanding § 20–105(a) of this subtitle, the Commission may spend up to $15,000 for day labor for any part of construction services without advertising for or receiving bids or proposals. Except as provided in paragraph (2) of this subsection, the Commission may enter into any type of contract under this subtitle that promotes the best interest of the Commission. The Commission: may not enter a cost–plus–percentage–of–cost contract; and shall prohibit a cost–plus–percentage–of–cost subcontract under a contract with the Commission. The Commission may only enter into a design/build contract for a facilities construction contract with costs exceeding $2,000,000. The Commission may reject any bid or proposal. The Commission may require a contract to be secured by bonds, penalties, and conditions. Security authorized under this subsection is enforceable in any court of competent jurisdiction. The Commission: may adopt regulations to establish a prequalification process for bidders or offerors; and shall adopt regulations to govern discussions held with offerors under § 20–105(c)(3) of this subtitle.