The Sewer System – Basic Info & Pressure Tests

It takes both homeowners and sewer agencies doing their part to keep the sewer system from overflowing into the environment. The drawing below provides an overview of the requirements and best practices of a sewer system.

The Sewer System: A Shared Responsibility

Sewer Pressure Test

A Sewer Pressure Test is required to ensure there are no leaks or cracks in the sewer lateral between your home and the property line cleanout.  A leaking sewer lateral can cause inflow and infiltration (I&I) into the NTPUD’s sewer system, which causes increased pumping costs to the NTPUD and our customers.  All sewage collected in the District’s system is pumped through the District and then up and over Dollar Hill into the Truckee River Interceptor that flows to the Tahoe-Truckee Sanitation Agency (T-TSA) treatment in Truckee. Groundwater in the system caused by leaking sewer laterals, mains and manholes can increase during a significant rain event and during the Spring melt season.

2016 vs 2017 Sewer Flows

This chart illustrates how significantly infiltration and inflow can impact the flows (and cost) in the District’s sewer system.  The difference in the flows in the system (shown in the red bars on this cart) in 2017 is significantly higher following during a large winter with rain events vs the drought year of 2016.

When does a sewer pressure test need to be performed?

  1. Remodeling of the house, building or property served to an extent of more
    than fifty percent (50%), as determined by the District, or
  2. Installation of additional toilet or drainage facilities in the house, building
    or property served, or
  3. Change of use of the house, building or property serviced from residential
    to business or commercial, or from non-restaurant commercial to restaurant commercial, or
  4. Upon repair or replacement of all or part of the private sewer, or
  5. Upon addition to structures of living quarters, such as guest cabins on the
    property served or plumbing of garages into living quarters, or
  6. Prior to close of escrow upon sale of the house, building or property served,
  7. Upon determination of the General Manager that the cleaning and testing is
    required for the protection of the public health, safety and welfare.

How is a sewer pressure test typically performed?

  • The test section is from the building cleanout to the property line cleanout.
  • An air test is performed by plugging each end of the lateral and applying 3.5 psi to the section under test. If the loss exceeds 1/2 psi in 5 minutes the test may be attempted one additional time. The second loss of pressure of more than 1/2 psi in 5 minutes constitutes failure.
  • If the line fails, the owner is responsible for correcting the problem and scheduling a new test.

What is the cost to perform a test?

Cleaning and testing requirements prior to escrow are waived if:

  1. The existing building sewer has a passing test within a prior five (5) year period approved and on file with the District; or
  2. If the building sewer has been installed and has a passing test within a prior fifteen (15) year period approved and on file with the District; or
  3. Upon determination by the General Manager.

View a list of local plumbing contractors and sewer pressure testing companies (PDF).
Note: The NTPUD does not promote any business or its representatives. This list represents a sample of local plumbers, excavation contractors, or sewer pressure testing companies. You may choose any company regardless of their location or affiliation.

Sewer pressure tests are performed during normal business hours.  Please call the office at least 24 hours in advance and let them know you need to schedule a sewer pressure test.  

The information above is a basic overview of the sewer pressure test.  View the District’s Sewer Ordinance for detailed Pressure Test Information.