The Sewer System - Basic Info & Pressure Tests

The Sewer System - A Shared Responsibility

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. 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 can show 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 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. New construction
  2. Addition of a toilet or living quarters
  3. Change of use (e.g. residential to business or vice versa)
  4. Repair/replacement of building sewer
  5. Prior to close of escrow 
  6. Upon determination of the General Manager to protect public health, safety, or 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.  
  • The cost is $200 ($175 to witness the test and $25 for the certificate) and the certificate is good for 15 years.  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 knowledgeable individual that has the equipment and to perform the test.   
  • 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 Sewer Ordinance for detailed Pressure Test Information.