None, except that on parcels or lots of less than fifteen thousand square feet in area and recorded as a separate lot in the office of the county recorder prior to the enactment of Ordinance No. 1010 (1954), the parcel or lot may be occupied by not more than one dwelling unit. Regulations shall be the same as required in the R-1 zone; provided, that all buildings shall be located not nearer than one hundred ten feet from the centerline of any existing or planned public street or highway. (Ord. 4970 § 1, 2019; Ord. 2709 § 3, 1982; prior code § 17.36.030)