st rooms. (Amended by Ord. No. 107,884, Eff. 9/23/56.) DWELLING, ONE-FAMILY. A detached dwelling containing only one dwelling unit. (Amended by Ord. No. 107,884, Eff. 9/23/56.) DWELLING, TWO-FAMILY. A dwelling containing two dwelling units. (Amended by Ord. No. 107,884, Eff. 9/23/56.) DWELLING UNIT. A group of two or more rooms, one of which is a kitchen, designed for occupancy by one family for living and sleeping purposes. (Amended by Ord. No. 107,884, Eff. 9/23/56.) DWELLING UNIT, LOW INCOME. (Deleted by Ord. No. 180,308, Eff. 12/7/08.) DWELLING UNIT, MODERATE INCOME. (Deleted by Ord. No. 180,308, Eff. 12/7/08.) EDUCATIONAL INSTITUTIONS. Colleges or universities supported wholly or in part by public funds and other colleges or universities giving general academic instruction as prescribed by the State Board of Education. EFFICIENCY DWELLING UNIT. A room located within an apartment house or apartment hotel used or intended to be used for residential purposes which has a kitchen and living and sleeping quarters combined therein, and which complies with the requirements of Section 91.4930.2 of this Code. (Added by Ord. No. 138,456. Eff. 5/30/69.) ELDERCARE FACILITY. One functionally operated facility, which provides residential housing for persons 62 years of age and older, and which combines in one facility, two or more of the following housing types: Senior Independent Housing, Assisted Living Care Housing, Skilled Nursing Care Housing, and/or Alzheimer’s/Dementia Care Housing. A minimum of 75 percent of the floor area, exclusive of common areas, shall consist of Senior Independent Housing and/or Assisted Living Care Housing. (Added by Ord. No. 178,063, Eff. 12/30/06.) ELEVATION. Vertical distance in feet above sea level. (Added by Ord. No. 181,624, Eff. 5/9/11.) ENCROACHMENT PLANE. An invisible inclined plane sloping inward at a forty-five degree angle from the vertical extension of the required front and side yard setbacks that originates at a specified height. A building may not intersect the encroachment plane. The encroachment plane restriction does not apply to roof structures and equipment as allowed by Section 12.21.1 B.3. For the purpose of this definition, height shall be measured from the existing or finished grade, whichever is lower, along the required front and side yard setbacks. Figure 12.03-1: Encroachment Plane diagram.