Except for setbacks along major streets as required by Chapter 17.86, there shall be established and maintained:
(B) Front yard requirements. Front yard requirements are as follows:
(1) A front yard having a depth of not less than 25 feet, provided that no front yard need be deeper than the average depths of the front yards next thereto on each side, but in no case may the yard be reduced below 20 feet. A vacant lot or a lot occupied by a building with a front yard more than 25 feet deep shall be considered as having a front yard 25 feet deep;
(2) For special conditions, the provisions of § 17.64.040 shall apply;
(C) Side yard requirements. Side yard requirements are as follows:
(1) Each lot shall have a side yard on each side of not less than 15 feet, except as otherwise provided;
(2) For special conditions, the provisions of § 17.64.040 shall apply;
(D) Rear yard requirements. Rear yard requirements are as follows:
(1) Each lot shall have a rear yard of not less than ten feet, except as otherwise provided;
(2) For special conditions, the provisions of § 17.64.040 shall apply.
(`78 Code, § 17.06.100.)