Symptoms of Sewer Drain Clog

Bathroom faucet
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A sewer drain clog is a very serious problem that can be considered a plumbing emergency and a distinct health problem. Since the sewer water has no place to go, it will all come back up into the household plumbing system in one way or another. When you have a sewer drain clog, you should not use any of the plumbing in the home until the stoppage is cleared.

If you suspect that you have a sewer drain clog, it is important to confirm this and clear it as soon as possible.

There are several signs that you may have a sewer drain clog:

Multiple Fixtures Are Clogged

A very obvious sign of a sewer drain clog is when more than one plumbing fixture backs up at the same time. Toilets, in particular, are affected by this, but other fixtures can also be involved. If you suspect that you have a sewer drain clog, start by checking other fixtures in the home.

Unusual Reactions When Using Fixtures

The next thing to look for when you suspect a sewer drain clog is any unexpected or unusual reaction when using plumbing fixtures.

  • Toilets: Toilets have the most direct path to the sewer and the biggest drain line in the house, so if there is a problem with the sewer drain, you will first notice it here. It is rare to have a main line sewer stoppage and still have toilets working correctly.
  • Tub and shower: Other drains typically affected by a main line stoppage are those in the tub and shower. This is due to the fact that they sit at a lower level than sink drains. Check whether the tub and shower drains are blocked if you suspect a sewer drain clog.
  • Flush the toilet: If flushing the toilet results in water backing up or coming up into the tub or shower, this is usually a clear sign of a sewer drain clog. The flushed water that cannot go down the sewer drain flows back up the pipes and comes out at the lowest point, which is usually the shower drain.
  • Run the sink: Another strange reaction to look for is trapped air in the plumbing system. Do this by running water in the sink closest to the toilet for a minute or so. If the toilet bubbles or you can see the water level in the toilet rising, then the clog is very likely in the main sewer line and not in the toilet.
  • Washing machine: An unexpected sign of a sewer drain clog can happen when you run the washing machine. If the water draining out of the washing machine causes the toilet to overflow or backs up into the tub or shower, it could be a sign the sewer main is clogged.​ Note: This symptom can just be a washing machine and shower problem and not a sewer drain clog. If the toilets are still flushing fine while this occurs, then this is likely due to a washing machine stoppage and not a sewer main.

Drainage at the Clean-Out

If you have a main line clean-out, you have an additional way of verifying a sewer drain clog. Locate the clean-out if you don’t already know where it is. Open the clean-out by either unscrewing or pulling to remove the cap. Check the clean-out for any waste or water that may be backing up there. Normally, no water should be coming up the clean-out pipe. If water is flowing up and out of the clean-out or standing in the pipe, this confirms that you have a main line sewer stoppage.

Once you have verified a sewer drain clog, you can move on to clearing it. Clearing a sewer drain requires a sewer drain snake. You can either call a professional plumber or rent the machine and clear it yourself. Either way, a sewer drain clog should be cleared as quickly as possible.