The rear yard setback line shall be parallel to the rear property line and extend the full width of the lot for not less than the following depths: where the rear property line abuts another lot, the rear yard shall be twenty feet deep; where the rear property line abuts a street, the rear yard shall be fifteen feet deep, except in the R-1C zone, where the rear yard shall be ten feet deep; where the rear property line abuts water, an alley, or private way, the rear yard shall be ten feet deep, except in the R-1L zone, where the rear property line abuts water the rear yard shall be fifteen feet. (Ord. 92-8 § 12, 1992; Ord. 89-1 § 1, 1989.)