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Tips for Unclogging Main Sewer Line

sewer line that was clogged & craacked
Sewer issues, such as a clogged main sewer line, can be incredibly frustrating for homeowners to handle, and not to mention expensive. However, if you notice a funny smell from your sewer or backed-up toilets, the only solution is unclogging. Main sewer line clogs can frequently be resolved with simple DIY projects, but sometimes you need to call in the professionals to get it properly cleaned out.
In this post, MT Drains & Plumbing will tell you how you can unclog your main sewer line by yourself and when you should call us to do the dirty work.

Why Would You Need Unclogging – Main Sewer Line Explained

In some cases, the main sewer line can clog if you dump things that don’t flush well down the pipes. This applies particularly to oils (usually from cooking) and paper items that don’t completely dissolve in water. Sanitary products such as wet wipes, feminine hygiene products, and even thicker toilet paper can cause an obstruction in your main sewer line and back up water and waste through your toilet. While the main sewer line pipe is usually 6 inches in diameter and doesn’t clog easily, a lot of loose material can still pose a risk over a long time.
More often, it’s the neighbouring trees that cause a clogged sewer line. Tree roots are naturally attracted to the hot and moist sewer lines passing through the soil. Small roots can creep in through cracks or looser joints in the pipes. Because sewers can be full of nutrients required for abundant plant growth, the roots will quickly spread throughout the sewer line. Eventually, the roots will overgrow the entire sewer line diameter and clog it by itself. But before that can happen, debris such as toilet paper or other hygiene products will snag on the outlying roots and pack up in the sewer line until nothing more can go down.
The most obvious sign of a main sewer line clog is slowly running drains. If it takes an unusually long time to drain the water in your shower or sink completely, and you notice it happening with all the drains in your home, the main culprit is the main sewer line to which all pipes connect.
Another more disruptive sign of a clogged main sewer line is backed-up showers and toilets. If you flush your toilet and there’s nowhere for the water and debris to go, the water will run up the lowest drain in your house, usually the basement or the bathroom drain. Water backing up the drain can also happen at the washing machine, showers, baths, or sinks. Cleaning the backed up water can be a messy and smelly job, and you won’t have a place to dispose of the wastewater since it will just repeat the problem if you flush it down.
Do note that if only one of your drains is backing up consistently, the problem usually lies before the main sewer line. In that case, only the drain pipe in that room will need unclogging. Main sewer line servicing is only required if all the drains in your house are malfunctioning.

Locating the Main Sewer Cleanout Line

Usually, you can access the main sewer line directly via the sewer cleanout. The sewer cleanout line is a small capped white pipe located a few feet from your house, between the house and the city sewer or your septic tank. The pipe is usually four inches in diameter and sealed with a screw-on cap. Sometimes it’s covered under shrubbery or soil after landscaping.
The main sewer cleanout can also be located in your basement, if you have one. Additionally, some rooms might have separate sewer cleanout openings for easier access. You can use those to solve more localized issues.
Once you’ve located the main sewer cleanout line, turn off the water supply to your house and unscrew the cap. A pressure change in the main sewer line can sometimes cause blocked-up water to run through the sewer line, resolving a smaller clog on its own.

How to Unclog the Main Sewer Line Chemically

Most often, a smaller clog can be resolved with a homemade solution. You can use hot water or a mixture of water and vinegar to flush a smaller clog down the main line and resolve the problem, though usually only temporarily. If your sewer line is clogged due to tree roots, you can use root-killing chemicals to fix the problem.
You can purchase a copper sulphate solution at most home improvement stores to kill the tree roots in your sewer. Before that, however, check if your area allows the use of copper sulphate. Additionally, you can’t use copper sulphate if you have a septic tank. You can flush the solution down your toilet or use it directly on your sewer cleanout pipe. Do note that copper sulphate can wash down too quickly and you might need to repeat the treatment a few more times to clean your pipes completely.
If you can’t use copper sulphate, look for some root-killing foam instead. The foam sticks to the pipes and does a better job of cleaning your sewer line. You can pour the chemicals into your sewer cleanout line to reach the roots directly.

Unclogging Main Sewer Line with a Pressure Hose

If you have a pressure hose available, you can insert it into the sewer cleanout, both up and down the pipe, to unclog the sewer pipes. To get the best results, use a dedicated sewer jetter attachment on your pressure washer and run the hose at least one foot down the pipe before turning the washer on. The pressurized water will make short work of clogs and smaller tree roots, clearing up your main sewer line without calling a plumber. You’ll know that the clog is cleared if water starts running through your pipes again.
Before you start, ensure that you’re using proper eye and skin protection. If any wastewater splashes back onto you, clean up immediately. Pressure washing the main sewer line might not be the safest task, but it’s reasonably effective at resolving most clogs.

Call a Professional

More severe cases of clogged main sewer line and drain back-ups will need to be handled by a professional plumbing service. MT Drains & Plumbing has a comprehensive draining service that includes a camera and video inspection of your pipelines, as well as chemical and mechanical cleaning of your sewer lines. Call us anywhere in the greater Toronto area and schedule your appointment. We work around the clock to ensure the best service. We offer free on-site estimates for unclogging main sewer line services, and our experienced technicians can get to work on your clogs in no time.


Paul S

Paul has more then 20 years in basement waterproofing and plumbing projects experience. Looking for an advice from an expert plumber? Make sure to read Paul's articles about residential waterproofing and plumbing projects in Toronto.

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