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Sewer Line Backflow Valve Problems

Theresa Jordan lives up in a suburb of Chicago, Arlington Heights, IL. But she's got a very big problem with backflow valves in her sewer line that are now creating backups in her home. She can tell the story much better than I can. Here it is:

"Where I live, we have combined storm and sanitary sewer and during extreme rainstorms, we will experience flooding as water will back up through the floor drains in our basement.

After the third time of this happening in 13 years, we decided to install a village-approved Flood Prevention System, which is basically a series of backflow prevention valves between our house and the street. This was quite expensive but we felt it was worth it to fix the problem.

But three months later, my pipes were backing up - which had never happened before, in 13 years.  I called the original plumber and they came and rodded out and flushed everything.

They put a camera thru and told me all my pipes are in perfect shape, no cracks or roots anywhere.  The problem is that I have almost no pitch on the main line going out to the sewer, and while it was apparently never a problem before, the extra added resistance from the new check valves is enough to slow everything down and cause too much sludge to build up.

I was advised the only thing I can do is refrain from ever using my garbage disposal and once a week, fill up my bathtub and let it drain at the same I flush all the toilets in the house.  Is that even a real thing?

Is there really nothing else I can do?  And shouldn't somebody have mentioned that fixing the flooding problem might create this other problem?  I can't imagine that in my neighborhood of older homes that nobody else has a pitch problem.  At this rate I will have to get my pipes rodded out 2-3 times per year, which is not cheap.  I appreciate any advice you might have.  Thank you!"

Luckily for Theresa, I've been a master plumber for over 35 years and have installed hundreds of feet of sewer line.

Theresa, I know many people that suffer like you do with sewer backups from combined sewers. It's a shame.

If you've not already done this, I urge you to put anything of value at least four feet in the air in your basement. Things of great value need to be stored higher up in the house. Why? There will come a day when the backflow valves my fail in the partially OPEN position and your basement floods again.

Let's talk about your disposal. You can continue to use it. But I need you to do two extra steps each time. Before you go to grind food, fill a pitcher with water. As you start to grind the food, keep the cold water on and pour the pitcher of water into the disposal to help dilute the sludge.

As soon as you turn off the disposal, put the stopper in on top of the disposal. Fill the sink with water. Do something else in the kitchen as this happens so you don't waste time. Once the sink is filled, then pull out the stopper and turn on the disposal as the water flows out of the sink. This not only cleans out the disposal ensuring it never stinks, it really helps to ensure all the sludge makes it to the city sewer. You can flush a toilet in the house about ten seconds after the sink drains for extra insurance.

Now, to prevent future backups it is pretty simple. It's a slight hassle, but very much worth it. I've recommended this for years for people that don't have the sewer backflow valves like you have.

Once a week, you need to fill up every sink, tub, etc. with water. At the SAME TIME getting help from the family, you open the drains. FLUSH all the toilets at the exact same time.

This giant slug of water rushing to the sewer should help keep everything open.

Yes, you should have been told you would have to do this, but it's a small price to pay - in my opinion - to not have horrible sewage filling your basement when the next monster storm comes.

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6 Responses to Sewer Line Backflow Valve Problems

  1. In Canada many municipalities have outlawed the the use of these garbage disposal units in favor of green bin recycling. Apparently the disposal units place a heavy burden on the sewage processing plant.
    You should consider removing the unit as part of the solution.

  2. Tim, the lady didn't say if the valve was installed inside or out side the house but either way most back water valves have a 1/2 inch to 3/4 inch drop through the body it self which would require to replace at least 8 foot of discharge pipe just to keep existing fall in sewer line, if that was not done there would be a blockage at the valve instantly. I hope the new valve has clean out sleeve going to top of valve for cleaning. Flushing the line once in awhile helps but doesn't correct poor installation .
    Illinois plumber since 1978

  3. I have a backflow valve between the street and the house. . I removed the insert a couple of years ago due to a backup in the house. I want to reinstall the valve housing. How does it fit ? Flapper up or flapper down?

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