Sewer Lateral Pressure Testing

Over time, sewer pipes age and can crack.  Cracks can cause leaks and contribute to inflow and infiltration (I&I) into the sewer system.  I&I occurs when storm or groundwater enters the sewer system.  During significant storm events, large amounts of I&I can overwhelm the sewer system and contribute to sewer overflows.  To help reduce I&I impacts to the sewer system, the District inspects all District owned sewer mains, laterals, and manholes on a regular basis and makes repairs as needed.  To help reduce I&I impacts associated with private home sewer laterals, the District requires that homeowners complete and pass a sewer lateral pressure test. 

What is a sewer lateral?

A sewer lateral is the pipe that conveys sewage from a building’s plumbing to the District sewer collection system.  The property owner is responsible for the upper sewer lateral only – the part on private property.  The District maintains responsibility for the lower sewer lateral that runs from the property line to the sewer main pipeline.

When does a sewer lateral pressure test need to be performed?

  1. New construction
  2. Remodeling of a house, building, or property served by the District's sewer system
  3. Addition of plumbing fixtures or living quarters
  4. Change of use (i.e. residential to commercial or vice versa)
  5. Upon repair or replacement of the building sewer
  6. Prior to close of escrow unless the lateral has passed a pressure test in the last 5 years or the lateral was newly installed in the last 10 years
  7. Upon determination by the General Manager to protect public health, safety, and welfare

How is a sewer lateral pressure test performed?

  • The tested lateral section runs from the building cleanout to the point of service or property line cleanout.
  • An air pressure test is required. Air testing consists of plugging each end of the lateral and applying 4 pounds per square inch (psi) of pressure to the lateral section.  The lateral must hold at least 3.5 psi for 5 minutes.  If the lateral pressure falls below 3.5 psi, the test may be reattempted one time.  A second loss of pressure constitutes a failure of the sewer lateral pressure test and signals that the lateral must be repaired or replaced.
  • If the line fails, the owner is responsible for necessary lateral repair and/or replacement and scheduling a new test.
  • The property owner is responsible for providing someone to perform the test.  This can be done by a plumber, contractor, home inspection professional, or any other qualified individual that has the equipment and knowledge to perform the test.
  • Sewer pressure tests are to be completed at the expense of the owner during normal business hours.  The test shall be witnessed by a District inspector.  Please notify the District 48 hours prior to testing at 530-583-4692.


The information above is a basic overview of the sewer lateral pressure test.  Please refer to the Sewer Code and Technical Specifications or more detailed information.