(1) It is the policy of this state that each housing authority shall manage and operate its housing projects in an efficient manner so as to enable it to fix the rentals for dwelling accommodations at the lowest possible rates consistent with its providing decent, safe, and sanitary dwelling accommodations, and that a housing authority may not construct or operate any such project for profit, or as a source of revenue to the city. To this end an authority may not fix the rentals for dwellings in its project at a higher rate than it finds necessary in order to produce revenues that, together with all other available moneys, revenue, income, and receipts of the authority from whatever sources derived, will be sufficient:
(a) To pay, as they become due, the principal and interest on the debentures of the authority;
(b) To meet the cost of, and to provide for, maintaining and operating the projects, including the cost of any insurance and the administrative expenses of the authority; and
(c) To create, during not less than the 6 years immediately succeeding its issuance of any debentures, a reserve sufficient to meet the largest principal and interest payments that will be due on such debentures in any one year thereafter, and to maintain such reserve.
(2) This section does not prohibit or restrict the activities or operations of a business entity created under s. 421.08(8).