I've heard numerous stories occurring throughout British Columbia where, apparently, inspectors enforced a rule that requires 15" of clearance from the centerline of a toilet to an adjacent finished wall or cabinet. I have yet to find the actual wording of this rule in any building code enacted in any part of Canada, however.
This good answer cites International Plumbing Code (IPC) section 405.3 as the basis for the 15" clearance rule. No part of Canada, however, seems to enact building bylaws based on the IPC. (In other words, if you're building in Canada you don't have to follow the IPC.) Rather, Canadian jurisdictions seem to adopt from the National Plumbing Code of Canada (NPCC).
According to that answer, IPC section 405.3.1 reads as follows:
405.3.1 Water closets, urinals, lavatories and bidets. A water closet, urinal, lavatory or bidet shall not be set closer than 15 inches from its center to any side wall, partition, vanity or other obstruction, or closer than 30 inches center-to-center between adjacent fixtures. There shall be at least a 21-inch clearance in front of the water closet, urinal, lavatory or bidet to any wall, fixture or door. Water closet compartments shall not be less than 30 inches wide and 60 inches deep.
I have searched through the BC Building and Plumbing Codes (which are based on the NBCC and NPCC) as well as the City of Vancouver's Vancouver-specific requirements and revisions of the BC codes. I have not yet found any generally-applicable rule similar to IPC section 405.3.1. Section 18.104.22.168 of the BC Building code contemplates distance from toilets for accessible washrooms, but that section only applies to accessible washrooms. Section 22.214.171.124 also requires grab bars on one side and 34" clearance on the other side of a toilet. Section 126.96.36.199 doesn't seem to apply to an ordinary residential toilet.
I'm specifically looking for the wording of this rule for the City of Vancouver. But I'm interested in any wording from any Canadian jurisdiction.