How to Test Your Sewer Lines for Leaks

It’s not something you think about every day, but your sewer lines are some of the most crucial parts of your home’s plumbing system. If you stop and think about it, it’s their job to make sure everyone in your family can go to the bathroom with ease and comfort. If they fail to function properly, you’re sure to end up with… a real mess. Maintaining all your plumbing systems is something you should do on a regular basis. Checking fixtures and pipes for leaks, your hot water heater to make sure it’s functioning at full capacity and your sprinkler system to make sure it’s doing its job are all routine tasks you should perform regularly. But what about testing your sewer lines? Do you even know where they are at? It’s vitally important to check these as well because if you do have a leak, it can spell real trouble for your home and the environment. Below we lay out the best methods to accomplish this important task.

Signs of Leaky Sewer Pipes

Knowing how to detect leaky sewer pipes comes first and foremost. How are you supposed to fix the problem if you can’t diagnose it in the first place?

Running Water

After you’ve used your toilet or any of the sinks in your home and you hear the faint sound of running water in your walls or overhead, it could be a sign that there is a leak somewhere in your sewer system.


If you notice unpleasant odors seeping out from behind your walls or outside in your yard, it’s another sign the pipes in your sewage system might be leaking.

Abnormal Grass Growth

Have you ever noticed how grass in a park is especially green if there are lots of ducks and geese around? The same can happen in your yard if sewage seeps out of pipes. Such an area will appear more lush, taller and moist than other areas. If you notice this in your yard, it’s highly likely that you have a sewage leak underground.


There’s nothing rats are attracted to more than the smell of sewage. If you find that all of a sudden you have an increase in rodent presence, it’s a good idea to check all your sewer lines for leaks. While no one wants a rat problem, their presence might be a sign that there is a much more serious issue you need to deal with.

Testing for Sewer System Leaks

Sewer Dye Test

A sewer dye test is something you can do on your own and should only cost you a couple dollars. All you need to do is insert a little bit of dye into your toilet or house trap. Next either flush your toilet a couple of times or run some water and wait to see if any dye appears. This might take up to a couple of hours if the liquid has to run through ground lines. If you notice dye after the process is completed, it’s a sure sign that you have a sewage leak, not a leak in your water line.

Sewer Camera

If you suspect that your sewer lines might be leaking, you might want to call your trusted plumbing professional right away and schedule a time for them to perform a sewer camera test. (You can even purchase one of your own, if you are considering making leak detection a hobby.) In most cases, your sewer lines are located under your home. The test starts by locating the main sewer line cleanout and inserting a special camera. From here, a plumber can watch on a monitor as the camera makes its way through the pipe noting any irregularities or weak spots in the pipe.

However, it’s important to know that a sewer camera alone has a hard time locating leaks. Since it is inside the pipe, it won’t be able to detect what is happening on the outside. If the results are inconclusive, you’ll want to perform some additional tests.

Test Balls for Drainage Lines

Test ball pipe plugs are used to block sewer drainage pipes. Balls come in a variety of sizes to fit different sized pipes. To start the process, make sure your main line sewer cleanout is clear of debris and liquid. Next, insert the test ball and inflate it so that it blocks the main line. Fill the sewer system with water and observe the water level for 15-20 minutes. If the water level drops, you have a leak somewhere in your sewer system.

The plumbing in your home is something that’s easy to take for granted. With that being said, it’s a highly complex maze of pipes, lines and fittings that require proper maintenance and upkeep. If something goes wrong, it can drastically affect your daily life. This is especially true when it comes to your sewer system. Armed with the proper knowledge of what to look for and how to perform some basic tests, detecting and locating sewer leaks is something you can do on your own for a minimal investment.

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