How many water closets can be served by a 3 inch horizontal branch line?

The correct answer is based on plumbing code regulations that dictate how many water closets can be connected to a horizontal branch line of a specified diameter. For a 3-inch horizontal branch line, plumbing codes generally allow a maximum of three water closets to be connected. This is due to the capacity of a 3-inch pipe, which is designed to handle the flow and drainage required by three water closets without risking clogs or insufficient drainage.

Understanding the limitations of pipe capacity is crucial in plumbing design. Each water closet has a certain drainage flow rate that must be accommodated by the pipe size. A 3-inch pipe can efficiently handle the discharge from up to three fixtures, ensuring optimal performance and compliance with plumbing standards.

While larger pipe sizes can handle more fixtures, the choice of a 3-inch pipe imposes a limitation on the number of water closets it can serve, which is essential for maintaining proper sanitation and preventing plumbing issues. Thus, three is the maximum recommended number for a 3-inch horizontal branch line according to plumbing codes.