Weblandlords who rent to section 8 tenants must charge a fair market rent, or fmr, and the general level for that rent is set in a series of tables by the local public housing agency. Webthe following sections provide information on the various rent calculations that the pha provides to applicants or participants at voucher issuance: To correctly calculate the housing assistance payment (hap), the pha first calculates the gross rent for the familyโ€™s unit.