Warning Signs That Your Main Sewer Line Needs Repair

By: John Garcia | Date Posted: November 17, 2021

Repairs to a malfunctioning plumbing system can cost thousands of dollars, and no homeowner wants to deal with that. In addition to the individual pipes inside your house, the main sewer line connected to them is part of your plumbing system. In most cases, major plumbing problems occur on the main lines, and you should try to avoid them whenever you can. If sewer lines are damaged, bathrooms can flood with sewage, pipes can burst, and repairs will be expensive.

A main sewer line issue can be challenging to identify. Many problems can go wrong with your plumbing, and some are impossible to diagnose without a professional’s help. A clogged main sewer line is quite common, but a broken main sewer line is a more serious issue that could leave you with a hefty bill.

Even if you’re a handyman, handling a massive task like your main sewer line might not be something you can accomplish well if you’re not a licensed plumber. And if you make a mistake in tinkering with this essential component of your home and worsening its condition, it might lead to the nullification of your home insurance. 

If you want a professional to handle this, check out the plumber Cambridge area that offers solutions to your plumbing concerns with a guarantee.

Signs That Your Main Sewer Line Needs Repair

Here are some of the most common warning signs that your main sewer line is in trouble:

  • Sewage backup and blockages. Occasionally, there can be sewage backups, but if the problem occurs every time you flush the toilet, it could be the main sewer line. For your drains to drain properly, they must pass through the main sewer line. You almost certainly have an issue with your main sewer line if you start experiencing blockages in more than one drain.
  • This can be a huge concern that will affect your family’s health, and cause a terrible inconvenience. If the dirty water leaks and soils your carpet, it’s considered category three water damage that warrants immediate replacement to prevent illnesses from occurring. As soon as you learn about this, contact your go-to plumber to rectify the issue immediately.
  • Foul odors. Air should not be able to escape from the main sewer line when it is intact. However, when you smell foul odors, it might mean there is a leak in the main sewer line. You should call a plumber if you notice the smell of rotten eggs and sewage emanating from your drains.
  • A foul odor is a serious matter.  It affects the air quality in your home. Illnesses may begin with a burning sensation on the chest, coughing, and wheezing and may escalate to difficulty of breathing and upper respiratory infection and might worsen anyone’s asthma condition.
  • Mold. Several problems can be caused by mold, but it could also be a damaged main line inside your walls. Water can leak from a crack in the line, creating mold growth in your home over time. The spread of mold on walls or ceilings is dangerous to your health, so contact a plumber as soon as you notice it.
  • Slow drains. It is common to experience slow drains, and almost all clogs can be solved by using a plunger or cleaning the drain. It is possible that a deeper blockage to the main sewer line is causing the slow drain if the simple unclogging methods do not work. There is a need to dig into the line itself to access the source of the clog, especially with mainline clogs, which are typically much larger and require more than simple unclogging methods.
  • Lush patches of grass. Your lawn may appear lusher than usual, but that might not be a good thing. A leaking sewer line can cause very green patches in your lawn because sewage acts as a fertilizer.
  • Lawn indentations. Check for lawn indentations as well as a lush lawn. As the soil near a cracked main sewer line becomes saturated, it eventually dissipates and dips. You may need to call a plumber if you notice changes in your lawn where your sewer line is buried.
  • Foundation cracks. In addition to being a plumbing nuisance, a damaged main sewer line can cause severe structural damage to your home. Untreated sewer lines can result in foundation cracks, sinkholes, or even sinkholes if left unattended.
  • Pools of septic waste. Seeing sewage pooling in your yard is one of the most obvious signs you have a major problem. There might be a cracked main sewer line in your yard if your yard smells bad and there is a puddle that won’t disappear.
  • Pests. A damaged main sewer line can also bring on the presence of pests in your home. Cracks and gaps in your sewer line easily allow rats and insects to enter. A plumber can visually inspect plumbing pests if you suspect they are infesting the plumbing.
  • Common fixes don’t solve the problem. Unless you’re a professional plumber, you’ll likely continue to have plumbing problems. In addition to detecting the cause of the problem, the licensed plumber can also fix or replace your main sewer line, if necessary.

Let the Professionals Handle It

Let the Professionals Handle It

Plumbing problems can seriously disrupt your home and daily routine. You can fix some plumbing issues yourself, but if it involves the main sewer line, you should call a professional service like Indiana Leak Detection (indianaleak.com/leak-detection/sewer-drain-leaks/) to have a look at it. You should leave the problem to the experts to ensure that it is completely fixed and that the work is done correctly.


  1. What are the signs that your main sewer line is broken?

  • Backups and blockages of sewage
  • The grass is lush and green
  • Bad odors
  • Mould
  • Drainage problems
  • Indentations in the lawn
  • Cracks in foundations
  • Septic waste pools
  1. What is the cost of repairing the main sewer line?

An average sewer main repair costs $2,556. The cost could range from $1,073 to $4,054, depending on the kind of damage. A complete sewer line replacement costs between $3,000 and $25,000. Back-ups of sewage may occur in basements, crawl spaces, or under landscaping and paved surfaces.

  1. What Are the Common Causes of a Blocked Sewer Line?

  • Pipes are severely damaged
  • Sewer line sagging
  • Infiltration of tree roots
  • Debris flushed down the toilet
  • Grease down the drain
  1. Is it possible for a sewer line to unclog itself?

It is possible for toilet clogs made of water-soluble materials to dissolve in the water and free up the toilet. In other words, toilet paper clogs can self-clear.

  1. Where is the main sewer line in my house?

Find a pipe that you know is a drain, such as a toilet or a sinking line (since all your drains lead to one central pipe). Then, find the larger pipe connected to the smaller one. Follow it through the basement or crawlspace until you reach the outside. It will lead you to your sewer line.

  1. What is the depth of the main sewer line?

A private sewer line can be as shallow as 18 to 30 inches deep, or as deep as 5 to 6 feet. Pipes buried deep in cold climates are protected from freezing in the winter by being buried further.

Thank you for reading!


John is the founder and chief editor of Homienjoy. With over 15 years of experience in the home improvement industry, John is passionate about helping homeowners confidently tackle their projects. Holding a civil engineering degree and working as a contractor, project manager, and consultant, John brings a wealth of knowledge and expertise to the Homienjoy community.

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