Final answer:
In the context of engineering, particularly plumbing codes, water closets should be spaced no closer than 8 diameters side-to-side and 15 diameters deep based on newer recommendations.
Step-by-step explanation:
The question concerns the spacing of water closets, which relates to engineering standards, particularly in the context of plumbing and building codes. The spacing between water closets set side by side is governed by these codes to ensure user comfort, accessibility, and maintenance. While an older rule of thumb indicated a distance of 5 diameters side-to-side and 7-8 diameters deep, the newer recommendation is to provide as much as 8 diameters side-to-side and 15 diameters deep for proper spacing. This provides ample room for privacy partitions, the comfortable use of facilities, and complies with the necessary safety and accessibility regulations.