Drain slope is the grade percentage or ratio at which a drainage pipe is installed to ensure adequate gravity flow. Minimum drain slope requirements are set by plumbing and civil codes based on pipe diameter — smaller pipes require steeper slopes to achieve self-cleaning velocity. The IPC (International Plumbing Code) specifies 1/4 inch per foot (2%) minimum for 3-inch and smaller drain lines.
Log grade shots, verify elevations, and generate inspector-ready field reports from your phone. No office work required.
Get started free →