How To Clear A Sewer Line Clog

Plumbing issues caused by clogged sewer drains can be expensive and frustrating for homeowners. AHS explains the signs of an issue and when to call in a pro.

clogged sewer lines

Clogged drains are a headache for many homeowners, but a clogged sewer line is on a whole other level. When a main sewer line is clogged, it can be difficult or impossible for any waste water, whether black or grey, to escape your home's plumbing system. Instead of flushing cleanly away, all of the waste that you try to expel from your home will stay in the pipes and eventually back up through your drains.

If you're experiencing this issue, you'll need to unclog the line. A sewer line cleanout isn't fun, but it's necessary to keep your home operating smoothly.

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Is My Main Sewer Drain Clogged?

Strange gurgling noises coming from your toilet. Water bubbling out of your shower when you run the washing machine. Perhaps you are wondering what it means if sewage is coming out of the shower drain? These are some of the signs that you may have a clogged main sewer drain line — a serious plumbing issue.

A clogged sewer drain line can impact the plumbing throughout your entire home. In severe cases, you may wind up with raw sewage backing up out of your drains. And no one wants that.

What Causes a Clogged Sewer Drain Line?

In most cases, particularly in older houses, tree roots can interfere with the smooth operation of your sewage system. Attracted to the warmth and moisture of a sewer line, tree roots creep in through tiny cracks or loose joints in the pipe. Feeding on the plentiful nutrients they find there, the roots grow and create a blockage in the sewer line. Eventually, toilet paper or other debris gets snagged on the roots, further preventing water from flowing through the main sewer drain line.

Flushing sanitary products, such as paper towels, facial tissues, feminine hygiene products or even extra-thick toilet paper, can also clog your sewer line. However, this is far less often a problem. Assuming these items make it far enough, sewer pipes are typically 6 inches in diameter. In other words, it takes a lot of loose material to clog them.

Signs of a Clogged Sewer Line

Watch out for these early warning signs of a blocked or clogged sewer line, so you can address the problem before it becomes an expensive emergency.

Your drains are all running slowly, despite your best efforts to clear them. If you've tried all of the DIY unclogging tips on this list and you still can't seem to find a fix, it's likely the blockage is in your sewer line.
Several plumbing fixtures are clogged at the same time. If your toilets, kitchen sink and tub or shower are all backed up, you probably have a clogged sewer line. Toilets have the most direct route to the sewer, as well as the biggest drain line. If the clog is in your sewer line, you're likely to experience trouble with your toilets first. If your toilets are working fine while other fixtures in your home are still slow to drain or are backed up entirely, you probably don't have a stoppage in your main sewer line.
When you flush the toilet, water backs up into or comes up in the tub or shower. When your sewer line is clogged, the water can't go down the drain. Instead, it flows back up the pipes and comes out at the lowest point — usually the shower drain.
When you run water in the bathroom sink, the toilet bubbles and gurgles. The bubbling is due to air trapped in the plumbing system. Run the water in the sink closest to the toilet for about a minute. If the toilet bubbles (gurgles) or the water level in the toilet rises, you may have a clogged sewer line.
When your washing machine drains, the toilet overflows or water backs up in the tub or shower. If the toilets are still flushing fine, you probably don't have a blocked sewer line.

A single slow-flushing toilet is not usually a sign of a backed up sewer line, nor is a single slow-flowing or easily clogged drain in your home.

Usually, you'll start having problems with all of the drains in your home, but especially the toilets — and it'll be all of the toilets at once. If all of your toilets cause other drains to overflow when they're flushed, or if they overflow when another fixture is used, don't worry that you don't know how to plunge a toilet properly — the problem is your sewer line, which, unfortunately, is a much bigger concern.

If you think your main sewer line is clogged, you can go outside and remove the cap on the main line drain pipe to release the pressure in the system. Be careful and stand to one side while you're pulling it off — any waste material that has backed up in your home's plumbing will come spilling out. This should allow your pipes to drain so that you (or a plumber) can get to work removing the clog.

Diagnosing a Clogged Sewer Line

Pinpointing the cause of a clogged sewer line may require a camera inspection, in which a camera can be inserted down into the line to look for areas where the line is broken or collapsed, or where roots are penetrating the line. It's a good idea to have the problem diagnosed via camera inspection before you start pouring chemicals into your main sewer line or trying to clear the line via auger, high-pressure water or other means.

If there's a break in your sewer line, you would be wasting your time trying to clear the line with an auger, and there's no need to add potentially dangerous and toxic chemicals to the mix, either. If your line is collapsed, you'll need to have it replaced.

How to Unclog a Sewer Line

A clogged sewer line can make your home unlivable. With no working toilets or sinks, you can't safely remain in your home. Luckily, you can take immediate action to restore your plumbing system to a state of good health, so that you and your family can get back in your home.

Release the pressure. When you first notice the symptoms of a clogged sewer line, turn off the water at the main supply (or street level). Survey your yard, basement or roof and see if you can find your sewer cleanout line. This is usually a short, white pipe about 3 to 4 inches in diameter and sealed with a screw-on cap. Once you've identified the cleanout line, remove the cap. This should release the pressure in the sewer line and force any water that has backed up into your home to drain.
Chemical drain cleaning. If tree roots are the culprit behind your sewer line clog, you can use chemicals to remove them. Some plumbers recommend flushing copper sulfate down the toilet to kill tree roots, but this substance flushes away quickly, meaning you may have to repeat the application several times in order to clear the clog. Be aware that copper sulfate is not safe for septic systems and its use is prohibited in some municipalities. If copper sulfate isn't a viable option for unclogging your sewer line, try flushing a root-killing foam containing the herbicide dichlobenil down your toilet. The foam sticks to the pipes and kills the tree roots within a few hours. However, it still may take a few months for dead roots to be completely flushed from your sewage system.
Mechanical drain cleaning. Sewer cleaning professionals have a few tools at their disposal for unclogging main sewer drain lines. Among the most effective is a specially designed, flexible cable that's popularly known as an auger or drain snake. The auger is often power-assisted — some are even truck-mounted — and can be fed into the sewer line in sections until the plumber is able to reach and break apart the clog. Plumbers may also use a high-pressure water jet to blow the roots and other debris down the sewer line. While you can rent these tools and do it yourself, both can damage your pipes if used incorrectly. Cleaning a clogged sewer line is a job best left to the professionals. There are sewer drain cleaning services available to provide emergency plumbing service to clear drain lines 24 hours a day in most locations.
Camera inspection. If the auger or water jet doesn't unclog the sewer line, you can request a visual (camera) inspection to determine what's causing the blockage. The miniature camera can reveal cracks and breaks in the sewer pipe, as well as problems in the line that may require your local sanitation department's attention.

If you have to have your main sewer line inspected with a camera, the emergency plumber doing the work should use the camera data to mark the location of the sewer line on the surface of the ground using paint or some other marking tool. Knowing where the sewer line is can come in handy later, if you need to have part of the line replaced. You should also get a copy of the video footage from the camera inspection, which most plumbers can make available to you in a digital format.

How Much Does a Sewer Line Cleanout Cost?

Emergency plumbing services use a powerful, electric auger to slice through any soft material in your home's main sewer line, chopping it up and sending it on into the main sewer. Sewer drain cleaning will require a plumber to open the drainage cap on your main sewer line and feed the auger into the pipe until it hits the obstruction. The auger is even powerful enough to clean out tree roots from your sewer line. But the cost to have your sewer lines cleaned out can be substantial — it costs $350 to $450 to have your main sewer line cleaned out this way.

Plumbers can also use rotary auger equipment or high-pressure water tools to clear out clogs in branch lines in your plumbing. Branch lines are the lines that go from your fixtures to your main sewer line. It costs about the same to have a clog cleared out from one of your home's branch plumbing lines as it does to have clogs cleared from your main sewer line.

Does a Home Warranty Cover Clogged Sewer Line Drain Cleanout?

If you have a home warranty with American Home Shield, you can get plumbing clogs in your home's main sewer drain lines cleared for only the cost of a Trade Service Fee. Blockages in your lateral drain lines are covered up to 100 feet from the access point. To get home warranty coverage for your blocked sewer drain, you should file a service request with American Home Shield online or over the phone.

One of the best ways to protect both your home and your peace of mind is with a home warranty from American Home Shield. Our Systems Plan provides coverage for your home's plumbing fixtures and pipes. Get a free quote today.

If you're already an American Home Shield member, we're here for you when you need us. You can request service in MyAccount 24/7.