December 6, 2022

Sewer Laterals

The sewer is the last thing most people think about. But once it fails, that’s all people impacted think about.

A primary component of the City’s sewer system is actually owned and controlled by each individual property owner in Suisun City, and is the most prone to failure. But it’s also one of the easiest to maintain.

Sewer Lateral Basics

Diagram - Private Sewer Lateral

This component is the sewer lateral.  It is the pipe that connects your home or business to the public sewer main. Every drain in your home or building is connected to the sewer lateral that runs from your structure to the public sewer main in the street.

The vast majority of sewer backups are the result of a clog or failure in the sewer lateral.

Sewer laterals are accessed through cleanouts usually located in the ground just outside your home or building. These are often protected under round covers flush with the ground or pavement with the word “sewer,” “clean out” or “C.O.” imprinted on them.  If there is a sewer problem in your home, this is usually where the plumber will access your drains.

In some cases, particularly in newer neighborhoods, there is a second cleanout on a sewer lateral located near the sidewalk or street. This is often referred to as a curbside cleanout.  The purpose of this cleanout is to allow Public Works Maintenance staff to access the spot where the sewer lateral joins the public sewer main.

When one is present, the curbside cleanout is the demarcation of an upper and lower lateral.  The upper lateral runs from the house to the curbside cleanout, and the lower lateral runs from the curbside cleanout to the public sewer main.

Responsibility & Maintenance

Sewer laterals and public sewer mains are typically constructed as part of a new subdivision or at the time of construction.  When the project is complete, the public sewer main is dedicated to the City and the sewer laterals and cleanouts transfer to the owner of the home or building.

In most communities, including Suisun City, the entire sewer lateral – from the house or building to the public sewer main – and all cleanouts are the responsibility of the property owner to inspect and maintain.

In situations where there is a curbside cleanout, Public Works Maintenance will take responsibility for the lower lateral. The upper lateral and the curbside cleanout remain the responsibility of the property owner.

Clogs in sewer laterals are often the cause of backups into homes and buildings. Property owners can install backflow prevention devices at their sewer lateral cleanouts to help prevent backups.  While these devices provide some protection, their manufacturers do recommend periodic maintenance.

The Sewer Smart Pamphlet below discusses sewer lateral maintenance and backflow devices in some detail.


  • Sewer Smart website
  •   Sewer Smart Pamphlet (560.8 KiB, 4,042 hits)
    This pamphlet provides information regarding sewer laterals, property owner ownership & responsibilities, and maintenance tips to keep your sewer lines flowing.

  •   Sewer Smart Pamphlet - Fats, Oils & Grease (2.0 MiB, 3,506 hits)
    This pamphlet contains information on why Fats, Oils & Grease (F.O.G.) are the main reason your sewer line will backup, and how to help prevent it from happening to you.