What is a cleanout (sewer cleanout)?

A sewer cleanout is an access point in your home's main drain line, typically located in the yard or basement near the property line. It consists of a length of pipe with a removable cap or plug that allows plumbers to reach and clear the sewer line when debris, roots, or buildup create a blockage. Most homes have at least one cleanout, though properties with long drain runs or multiple drainage zones may have several.

When a plumber needs to snake or jet your main line, they remove the cleanout cap and feed their equipment down through the opening. Without this access point, clearing a main line blockage would require more invasive and expensive work. Cleanouts are typically 4 to 6 inches in diameter and may sit flush with the ground or extend slightly above it. Over time, cleanout caps can corrode, crack, or become stuck, which is why having one in good working order matters for future maintenance. If you're unsure where your cleanout is located, a plumber can help you locate it during an inspection.

Finding and accessing your cleanout is the first step when dealing with slow drains or sewer backups. Professional drain and sewer cleaning services rely on cleanouts as their primary entry point for diagnosing and fixing line problems.