§ 1174-q. Construction and purchase contracts. The authority shall let contracts for construction or purchase of supplies, materials, or equipment pursuant to sections one hundred one and one hundred three of the general municipal law. Nothing in this section shall be construed to limit the power of the authority to do any construction directly by the officers, agents and employees of the authority or to contract with a public utility, for a term not to exceed five years, for the operation and maintenance of a water supply system acquired from said public utility.