How to Test a Sewer Per IPC

Home plumbing affects more than just the house.

The International Plumbing Code and many local codes require buildings to pass a sewer-pressure test before the building is deemed inhabitable. The primary reason for the test is to make sure the water pressure leaving the building and entering the sewer system is below maximum guidelines. IPC guidelines also require buildings to be retested when certain replacement plumbing projects are completed. The test can be completed with water exfiltration or with an air test.

Instructions

Air Test

1. Plug each of the laterals.

2. Apply 3.5 pounds per square inch of air pressure to the plumbing section.

3. Monitor the pressure lost after five minutes. To pass the test, no more than one half PSI should be lost at the end of five minutes. Local code may allow for a retest. You can tell how much PSI is lost by how much more psi you have to add to bring the level back up to 3.5 PSI.

Water Exfiltration Test

1. Plug the lateral and riser at the clean-out.

2. Surcharge the line with water until it is level with the foundation grade. The minimum water level must be at least two feet above the lateral invert at the sewer clean-out. If any fixtures are below that level, they must be plugged off for the test and a backwater valve must be installed.

3. After 30 minutes, measure the amount of water that was lost. More than 4 gallons of water loss for a four-inch lateral is a code failure. The city inspector may allow more water loss for larger laterals.

Tips & Warnings

• Check your local code. You may be required to have a city inspector on site at the beginning of testing to witness the test.

• IPC undergoes annual evaluation and revisions. Make sure you are installing plumbing based on the current code.

• Over time, your lateral will break down with wear. Local code may require you to register for a permit to replace the lateral and to pass an IPC sewer test before the city inspector will sign off on the work.

• Hire a licensed plumber to install any lines connecting to the sewer system and have the plumber on site for the sewer test. Failure to pass the test may mean redoing the plumbing and waiting for weeks before you can get another city inspector back out for a retest. The city inspector will not likely be willing to wait around while you make last-minute adjustment for an on-the-spot retest, so it is important to having the plumbing work done right the first time.

References

• City of Fernando: Sewer Testing Procedures
• Pikes Peak Regional Building Department: 2006 IPC Committee Code Review