what size pvc pipe for toilet drain
Standard Toilet Sewer Pipe Sizes. Always check local plumbing codes before you begin a plumbing project. If your home has one or two toilets, the standard toilet sewer pipe size is 3 inches. The sewer pipe connects to the toilet flange beneath the toilet, and this flange is a standard 3 inches. You cannot reduce the size of the pipe anywhere along the piping. If your home has three or more toilets, you must install a 4 inch sewer pipe for adequate drainage.