An authority shall fix the rentals for dwelling in its projects at no higher rates than it finds to be necessary in order to produce revenues which, together with all other available moneys, revenues, income, and receipts of the authority from whatever source derived will be sufficient to:
1. Pay, as the same become due, the principal and interest on the bonds of the authority;
2. Meet the cost of, and provide for maintaining and operating, the projects of the authority, including the cost of any insurance thereon, and the administrative expenses of the authority; and 3. Create, during not less than the six years immediately succeeding its issuance of any bonds, a reserve sufficient to meet the largest principal and interest payments which will be due on such bonds in any one year thereafter, and to maintain such reserve.