Space
The average toilet is 15 in. wide and about 28 in. deep. However, you’ll also need clearance on both sides and in front of the toilet. You’ll probably want at least 1 ft. on either side of the toilet and 2 ft. in front, but this is still a small space for a toilet. Code requirements may list minimum spaces, and they can vary by city and county. Contact your local building authority to find the minimum distance where you live.
Common Mistakes
You also have to install the plumbing to take cold water to and from the toilet. A common mistake is to use pipes that are too small. Check local building codes for these standards, also. You must also provide enough space for the shutoff valve for the toilet, properly align the tubes, and install the toilet level.