The Telltale Signs of a Clogged Sewer Drain in Your House (2025)

A clogged sewer line is a serious problem, and can even be considered a plumbing emergency. When pipes are blocked, wastewater has nowhere to go besides back up into your home, so if you suspect a sewer drain clog, you'll need to address the issue right away.

Adding any more water to the system will only make things worse, which means you will need to shut off the main water valve or stop using any toilets, sinks, showers, and tubs until the issue is fixed.

Addressing the cause and clearing the clog as soon as you notice any of the symptoms in this guide will help you start using the water in your home again as quickly as possible.

Is My Sewer Drain Clogged?

Some of the main signs of a sewer drain clog are more than one plumbing fixture—such as a the toilets, showers, or bathtubs—backing up at the same time, and smells of sewage around your toilets, showers, and sinks.

A clogged sewer drain can also cause the fixtures in your home to act up, so if you suspect a clog, you should check each of these spots for the following symptoms, starting at the bottom floor of your house:

• Toilets: Toilets have the most direct path to the main drain, use the biggest pipes, and are where problems usually start. You may notice that a toilet doesn't flush properly, or gurgles when water is running from other fixtures.
• Tub and shower: Drains in tubs and showers sit at a lower level than sink drains, and are also likely to be impacted by a clog. These drains might work more slowly than usual, and you may notice a change in water color or wastewater leaking into the tub.
• Sinks: Another symptom to keep an eye out for is trapped air in the plumbing system, which makes the water level in toilets rise or causes gurgling noises when you run the sinks in your house, especially the sink closest to the toilet.
• Washing machine: If the water draining out of the washing machine causes the toilet to overflow or backs up into the tub or shower, and toilets are also struggling to flush, the sewer drain is likely clogged.

Causes of a Clogged Sewer Line

Flushing the Wrong Products

Because toilets have the most direct path to the main sewer line, one of the most common causes of a clog is any product besides toilet paper repeatedly being flushed down. Items that can cause blocks include baby wipes and cleaning wipes (even if the label says they're flushable), paper towels, tissues, q-tips, and hygiene products.

Grease and Garbage Disposal Issues

Much like flushing the wrong products, using the garbage disposal incorrectly and pouring grease directly down your kitchen sink can also cause the sewer line to clog. If you put food down your disposal too quickly, it will not be broken down enough to move through the system.

Dumping used oil and grease down the drain will also cause issues once the liquids cool and solidify in the pipes, creating tough blockages.

Limescale

Over time, and especially in hard water areas, limescale will naturally build up in the sewer line as wastewater passes through. These mineral deposits will gradually start to block the pipe's opening, leaving a smaller space for debris to pass through. This will inevitably lead to complete clogs, and the hard build-up will need to be removed by a plumber with a professional jetting tool.

Roots and Ground Problems

Main sewer lines run outdoors and underground, and no matter how many preventative measures you take within your home, some issues are completely out of your control. Over time, tree roots can grow around and into the pipes, which will cause cracks and clogs.

The ground surrounding a sewer line can also move and cause it to drop due to construction, digging, or natural shifts in the soil. If this happens, the entire pipe might need to be replaced.

Clogged City Sewer

If you live in a city, town, or suburb, your home's sewer drain connects to a municipal sewer main under the street. If your house's main drain is backed up and your neighbors' are too, it's possible the city sewer main has a major blockage. Your home's fixtures will experience the same symptoms as they would with a clog in just your home, although city backups can cause enough pressure to actually force raw sewage into drains and flood bathrooms.

Full Septic Tank

In rural areas, wastewater and sewage does not flow into a municipal sewer system—it goes out to a septic tank and drainage field in your yard, where water gradually seeps down into the soil and raw sewage safely decomposes underground. The main drain in these systems can clog if the septic tank or underground drainage field is full or completely saturated, and cannot absorb any more waste.

What to Do If YourMain Sewer Drain Is Clogged

Firstly, do not run the water or flush the toilet. If you don't add water to your drain system, you can't make the problem worse. As an added precaution, you also can shut off the main water supply to the house.

If you suspect a clogged sewer drain, you can try a couple of the home remedies below which will help clear minor clogs, but will likely need to call a plumber or drain specialist to have the drain cleared.

Pour Boiling Water

If your home has metal pipes and the clog is being caused by food, hair, soap scum, or grease, simply boiling some water might be your solution. Once you have a kettle full of boiling hot water, slowly pour it down the drain of the sink or tub experiencing issues. Do this over the course of five to 10 minutes, then see if the drain is running smoothly.

Use a Plunger

A toilet plunger can actually be used to dislodge minor, surface-level clogs in any drain around your house. Remove the drain stopper, and fill your sink or tub with one to two inches of hot water. Then, create suction by sealing the plunger around the drain, and use the rapid back-and-forth motions you would with a toilet to see if water will start flowing down the drain again.

Call a Plumber

If neither of the above methods work, you will need to move on to more difficult solutions that could involve interacting with raw sewage, which should always be handled by a plumber. These professionals have special equipment, including hydrojetters and motorized augers (drain snakes) which can quickly and effectively remove large clogs in the main sewer drains so you do not have to interact with hazardous waste.

Clear the House Trap

Adrain clean-out fitting, or house trap, is a short pipe attached to a drain pipe with a threaded plug on the end. Although this is a fix best left to the pros in case there is any built-up pressure, those with plumbing experience can try unscrewing the clean-out plug with a wrench or pliers, and snaking the pipe.

However, you will need to be extremely careful of any wastewater flowing out once you unclog the clean-out. If any water leaks out of the trap during the unscrewing process, stop, slam the plug back down, and call a plumber immediately.

Upgrade or Clear Septic Tank

If you have a septic system and your sewer line has clogged, you will need to call a professional to pump out the septic tank. If the issue repeats, the system is likely isn't large enough for your home's needs, and a pro (or team) will need to take on major work, involving digging up the yard to make upgrades to the system.