A p-trap’s vertical distance from its bottom to the inlet pipe determines its effectiveness in preventing sewer gases from entering the laundry area. A typical measurement for a washing machine drain is between 18 and 24 inches, though local plumbing codes should always be consulted. This dimension ensures adequate water sealing while accommodating the high discharge volume of a washing machine.
Correct vertical positioning is crucial for proper drainage and odor prevention. An insufficient dimension can lead to siphoning, allowing sewer gases to bypass the water seal. Conversely, excessive elevation can slow drainage and potentially cause backups. Standardized plumbing practices have evolved over time to ensure optimal functionality and hygiene in residential and commercial settings.