Whenever the acquisition of real property for a program or project will result in the displacement of any person on or after July 1, 1972, the displacing agency shall assure that within a reasonable period of time prior to displacement, there will be available comparable, decent, safe and sanitary replacement housing which is within the financial means of such displaced persons. Regulations issued pursuant to Section 43-39-17 may prescribe situations when these assurances may be waived.