12 Pa. Code § 31.18
Only rents established or approved by the Agency may be charged for dwelling units in housing projects receiving a permanent mortgage loan from the Agency. In establishing or approving rents, the Agency will provide for rents which, together with other money legally available to the Agency or the mortgagor, will be sufficient to meet the debt service and the maintenance and operational requirements of the housing project unless such rents would cause rental vacancies in excess of 50% of the total apartment units in the property. The rental charges established by this section shall conform with the definition "moderate rentals" and "low rentals" as set forth in section 103 of the act (35 P. S. § 1680.103).
12 Pa. Code § 31.18
This section cited in 12 Pa. Code § 31.19 (relating to Tenant Selection Plan).