Your main sewer line isn’t something most homeowners think too much about – out of sight and out of mind.  And probably for good reason.  When you flush the toilet and everything goes down it’s all good right?

Ehh…maybe.  The thing is your sewer line is one of those things that works great until it doesn’t and when it doesn’t it can become an emergency pretty quickly, and costly to repair.

Many sewer line problems develop slowly over time until they reach the point where it causes sewage to start backing up into the line and sometimes unfortunately into the home.

So let’s take a look at the main issues that can cause main sewer line backups.

Root Intrusions

Root intrusions are one of the most common issues with the main sewer line and can happen in any kind of sewer line material be it plastic (PVC or ABS), clay pipe or even cast iron.

Root intrusions often take some time to develop.  That nice little 6ft tree in your yard when you by that new house?  In maybe as little as 15 years the root structure could expand and become large enough that it starts encroaching on your main sewer line if it runs through the front yard.

Root intrusions will start small, maybe something like this:

But ya know, they got in there because they were looking for water and in your sewer line they will find it and…..uhhh….fertilizer and will continue to grow and develop into something like this:

Once you reach this point you can start having real problems as toilet paper and other waste solids can start getting caught up and create a dam in the line.  You may start noticing slow flushes from the toilet but at some point it can cause a problem if a large amount of water is introduced into the line all at once, such as a washing machine entering the drain cycle.  If the dam has reduced the available volume in the line and cannot handle the amount of water introduced, it can back up into the house through the toilets and other means.

Fractures, Offsets, and Collapsed Pipes

Fractures are more commonly associated with clay pipe, but can also occur with cast iron or plastic.  Fractures are usually not an emergency on their own, at least when they first develop.  However fractures can make a line more susceptible to root intrusions as described above and also soil erosion if sufficient gaps develop related to the cracking. Fractures can appear like this:

Offsets occur when pipe segments separate at one or more joints and become displaced from each other.  If the offset is large enough then significant soil erosion can occur and there is even the possibility of generating a localized sinkhole around the offset area.  And again, it also offers a low resistance path for future root intrusion. Offsets can appear like this:

Collapsed pipes are just as the term implies – the structural integrity of the pipe has been compromised to such a degree that it collapses inwards on itself, frequently leading to a complete line blockage.  Collapses are very serious and should be addressed immediately. Collapsed pipes can appear like this:

Human Factors

If you surveyed 10 random people and asked them, “is it ok to pour bacon grease down your kitchen sink?” I’m willing to bet that almost universally the answer would be, “of course not”.  Yet people do introduce bacon grease and any other type of material not intended into their main sewer line all the time.

The problem with disposing of bacon grease in particular into the sewer line is that while it may have been hot and liquid when introduced, during it’s journey it will cool, congeal, and begin adhering to the walls of the sewer line before it reaches the city sewer connection.  As this builds up over time this can cause blockages and other issues.

On a personal level I can tell you that my wife and I moved last fall into a 10 yr old house.  Before we moved in I did my own sewer scope and about 65ft into the line encountered a piece of semi-rigid plastic from some CPG (consumer packaged goods) packaging.  Just sitting there.  How it got there was/is a mystery.

The point is, if something is small enough to fit into a main sewer line it probably has at some point at some home.

Soooooo……..should I get a sewer scope inspection with my home inspection?  Ultimately this decision is up to the client, but at GPI LLC this is some general guidance we give:

Sewer scope recommended IF:

• Home is 15 y.o. or older.
• Home inspection reveals instances of slow/delayed flushing action in emptying the bowl.
• There is evidence of substantial soil digging and/or removal from the front of the home out towards the city sewer connection.
• The seller discloses that sewer repairs were made and cannot produce a post-repair inspection report and/or photos or videos.

Sewer scope optional IF:

• None of the above applies

OR

• Seller had a sewer scope done within the last two years and will share the inspection report and any associated photos or videos.

Conclusion

So in short, sewer line inspections are always optional but never a bad idea.  Sewer repairs can be very expensive, so if an inspection is done and issues are noted they are something you would definitely want to negotiate with the seller before going to closing.