"French drain" in basement backing up


  #1  
Old 09-20-16, 10:40 AM
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"French drain" in basement backing up

We bought a very old house (built in 1875) this spring that has what was described to me by the previous owner as a "French drain" around the perimeter of the unfinished basement so any moisture could go down the slope and drain into the storm drain. The previous owner also had a dehumidifier running non-stop in the basement, and the excess water from this machine's drain hose drained right into the French drain.

We noticed the smell of stale water down there this week and then saw that the drain area was backed up with a few inches of water. I reached into the pipe and pulled out some gunk that seemed to be clogging it. A few hours later, the water level had receded quite a bit. This morning, I went down and saw that the water level was high again. I just had my wife check, and it is back down to mostly mud in the area now.

A few questions:

1.) Should we continue to run the dehumidifier 24 hours a day down here?

2.) Is the water level rising and receding around the drain normal? We haven't noticed any standing water before this week, and it has been relatively dry here in our area prior to this.

3.) Should I snake it myself/hire someone to come snake it if we are having standing water around the drain? I pulled what I could out with my hand, but can't reach in very far.

4.) Can someone explain the purpose of this type of drain? Why does the pipe seem to have two openings? Once facing outward (toward the center of the basement), and one pointing up (towards the ceiling)?

Thanks for reading and for any feedback/thoughts!


Here's the "French drain" in the basement:
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Here's further down the wall with the dehumidifier:
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Here's where the water drains into the pipe that (I assume?) takes it to the storm drain:
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Here's what the pipe looks like (hard to see in the previous picture, because it is muddy/dark):
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  #2  
Old 09-20-16, 12:52 PM
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The purpose of the French drain is to keep water soaked into the ground outside from coming up through where the foundation wall meets the floor slab and flooding the basement.

You may need to snake or jet the pipes to get rid of mud or other clogging material.

During some weeks of the year, depending on rainfall, it is not unusual for water to sit in the French drain but the water level should not rise up to basement floor level and overflow onto the floor.

Perimeter French drains are still in common use including in new construction but are usually in the form of a buried perforated pipe instead of being on the surface where the water is exposed and releases humidity requiring dehumidification and becomes musty. In most cases the water won't drain by gravity so a sump pump is required.
 

Last edited by AllanJ; 09-20-16 at 01:42 PM.
  #3  
Old 09-21-16, 10:01 AM
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Yup, sounds like it needs to be snaked. Over the years, they just get filled with gunk. You can try with a 25' manual snake and see if that helps. You may need to bring in someone with a larger snake if that doesn't work, but the $10 investment in a snake isn't a bad one.

Once the drain is cleaned out, any water that comes in should go right out, making it much easier to keep your basement dry.

It's common for older foundations to "leak", back then, they were built to hold up the house, not to provide a waterproof barrier. So for any non-concrete foundation house, you should run a dehumidifier and plan on some water seepage occasionally. You likely won't need a dehumidifier during winter months as the heating system should dry out most of the house for you.

Also, the dehumidifier draining into the french drain obviously works, but I don't like it. I would much rather drain it directly into the outgoing pipe. Why put the water back into the foundation for it to potentially evaporate back into the air?


Good luck with the old house, they are fun - and will keep you busy!
 
  #4  
Old 09-22-16, 10:37 AM
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Thanks for the info! I will look into the snake option and put it on my list of projects to have the dehumidifier drain into a pipe rather than the french drain.
 
  #5  
Old 09-25-16, 12:33 PM
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So, I planned on going and buying the snake today, and went downstairs to check on it before heading off to the store. I was surprised to find that the water was more backed up today and that there was raw human sewage floating in the water.

My understanding is that this french drain should be draining into the storm drain and not the sewer line, but obviously I'm either wrong or there's a crossed pipe somewhere. To complicate the equation, as I was standing there trying to figure out what was going on, the cycle on our washing machine ended and the water drained out of the washing machine. The previous owners had hooked up the drain line to go into the sewer line (as referenced in the picture below). As the water drained, I could see soapy water coming out of the pipe that the french drain is supposed to drain into.

Can someone help me understand what is going on? I thought the french drain line would go to the storm drain on the street, and the washing machine drain/sewer line would run out to the city sewer at street, but obviously I'm missing something.

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  #6  
Old 09-27-16, 09:03 AM
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It's definitely sounding like you have potential bigger problems. It may be worth bringing out a plumber with a snake and camera and have them just snake both drains. A camera will be able to ensure there aren't any bigger issues and to help confirm that they are all going the right direction.

I don't know what that pipe on the right is, it doesn't seem like a storm drain because of it's small size. It's rare to see a 2" pipe for any kind of storm drain.

Do you know if your area has separate storm/sanitary drains at the road? Or might they combine into one?
 
 

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