§ 29-9 GRADING OF LOTS.
   All building lots in areas annexed to the city after January 1, 1960, which are to be improved by any construction thereon, shall be graded, if grading is necessary, from the back of the curb or edge of an unimproved street, for a minimum distance of ten feet at a grade not to exceed five percent, plus or minus.
(1964 Code, § 20-8)