The standard pipe size for your sewer line is usually 4 inches. The local code will usually specify the required pipe material and size. Most jurisdictions have similar requirements for pipe sizes, but each jurisdiction may have slight variations and/or additions/deletions to the code. When it comes to sewer line sizes, a common misconception is that bigger is always better, which is not the case. Larger pipes spread the pressure required to help solid wastes move through the pipe. So, installing a larger pipe may slow the flow of water and cause water pooling.