Whether you own a home, or rent an apartment, few things are as scary as mainline back ups.

A mainline back up is when the main sewer line loses the ability to drain (fully, or partially), so that it affects the entire house.  Since water naturally looks for the lowest possible outlet, it is very common to take a shower in an upstairs bathroom, and find yourself with a flooded downstairs bathroom (due to the sewage escaping via a toilet or shower).  A more common tell-tale sign that your sewer main is clogged is flushing a toilet and finding the sewage backed up into your tub or shower.

As plumbing goes, sewer main backups are also one of the most misunderstood phenomena – not just for homeowners, but for less experienced plumbers as well.  Let’s start by examining what causes them.

What Causes Mainline Back Ups?

If you consider that a residential sewer main is 3”-4” in diameter, and the largest “access” to deliver sewage into the main is via the toilet (usually 2” or less), a sewer main that is backed up usually indicates an underlying issue with the line itself.  The most common causes are:

  • Tree roots finding their way into the sewer line, and growing inside of it (by far the most common cause).
  • Land-shifting or other factors causing the pipe to lose “grade” (the downward slope needed for the sewage to flow downhill), or create a “belly” in the line.
  • A broken or crushed pipe often cause by one or both of the factors above.
  • A separation of the sections of the pipe where they join (also very often caused by roots, and/or shifting soil)

There are many other causes for a potential sewer clog, but these are, by far, the most common.  Now that you know the causes, let’s look at the solutions.

How to Fix a Sewer Main Back Up:

Most home owners, and many plumbers think that running a sewer cable (also commonly called a “snake”) down the offending line is the best way to “fix” a sewer clog.

While “cabling” a sewer line, through an appropriate access point is a great way to temporarily restore flow, if you look at the most common causes of sewer back ups above, I am sure you will agree that it is not going to fix the issue(s) that caused the backup to begin with.  The only way to really fix the problem is by having a fully qualified, and professional plumber fully assess the situation, do his best to restore flow, diagnose the cause of the backup, and come up with a comprehensive plan to rid the problem for good.

It is, of course, your decision as to whether or not you use the fact that your service is restored to buy you some time to weigh your options, or get the problem repaired, so it never bothers you again.  Just make sure that you have enough information to be able to make that decision an informed one.

If you are looking for the right plumber in San Jose to take care of your mainline back up like a true professional, we would encourage you to call Allstar Plumbing for a no obligation, free estimate.  Just head over to our “Contact Us” page, or dial the number below.

We look forward to hearing from you.