How Do You Test for a Break in a Sewer Line System?

We can perform multiple diagnostic tests for sewer line breaks. Sometimes multiple tests are performed in a particular order in an attempt to rule out an event or to narrow down the location so that the next step can be determined.

Hydrostatic Pressure Test
The primary and most common test to determine whether a sewer line is functional is called a hydrostatic pressure test. We place a rubber test balloon in the main line, creating a stoppage point. This is usually done through the front main cleanouts, assuming they are accessible and in good condition.

From there, the sewer lines under the home are filled with water and subjected to pressure. We then mark a specific point, either in the cleanout or preferably a tub/shower in the rear of the home. The water should then maintain that set level without dropping for a period of 20 minutes.

Failure to hold and maintain that same level would require the test to be repeated to validate accuracy. If it does not hold, then based on the rate of water loss we can start to get an idea of what we are looking for—a complete separation versus a cracked fitting.

If this test is being done for post-foundation repair warranty purposes, a letter will be written acknowledging our findings regarding your records and warranty purposes. We always prefer to perform this hydrostatic test before the backfill of the pier excavation takes place. But if that isn’t possible, we can still perform the test.

Camera Inspection
If the hydrostatic pressure test fails, we typically follow up with a video inspection using a sewer camera. This allows us to look for obvious signs of failures, such as root infiltration, mud, bad fittings, bellies, etc.

However, this technique is somewhat limited in that the camera does not have a steering wheel to turn left and right into the various branch arms of the plumbing system. So we can only inspect the main line before moving to other cleanouts (or vents) in the house. Once a break or problem area is identified, we use a locator device to mark the spot(s) in question.

If your break or issue is not under the home or business but instead in the main sewer line going to the city sewer system (or septic system), this would typically be inspected via video sewer camera only. The problem spot is identified using the camera’s head and a locator device. This will give the location and depth and allow us to provide a price to make that repair.

Sewer Line Isolation Testing
If the camera does not allow us to identify anything obvious, the next steps would be to perform isolation tests of the various branch arms until we find the one that fails to hold. At that point, sometimes we cannot test any further without excavation and/or making a repair for the first known break. There are some occasional workarounds, but things become far more complicated and sometimes not practical or even possible without starting the repair process.

Smoke Test
Another test used to identify failures is a smoke test. This is typically used for portions of the sewer system that are above the slab (usually vents) and can be useful to identify where a sewer gas smell (foul odor) is being emitted.

The entire sewer system is filled with smoke, then we watch for any hint of smoke coming from an area where it should not be coming from. It is important to note that we never want to jump straight to a smoke test. There are steps to be taken for some obvious correctable issues first. There are also many things that can give false alarm smells, such as a rodent problem.

Contact Earl’s today for sewer line services including testing, camera inspections, and repair!