Gutter downspouts backing up

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  #1  
Old 06-18-19, 03:27 PM
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Gutter downspouts backing up

I have 2 downspouts on same side of house which connect to same underground PVC pipe which empties into street side. Not sewer.

During heavy rains water will back up and overflow at gutter connections. I had pvc line snaked and large roots were removed. Water rushed out when snake was removed so I thought problem was solved. However it happened again this weekend

It seems as this problem developed after I had new gutters installed. Is it a crazy idea that new gutters are more efficient and creating too strong a flow for pvc outlet pipe? Need larger diameter pvc perhaps??

also notice pvc outlet pipe has 90 degree angle about 1 foot underground.

Thanks!!
 
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Old 06-18-19, 03:36 PM
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Nothing wrong with your gutters. 3x4 downspouts move twice the volume of water as old 2x3s. But don't know what you had or have.

If you have roots in your pipes you might as well get them dug up and replace them. Because that will be a constant headache. They should be solid pvc (not drain tile), 1/4" per foot slope if possible. Larger diameter (6") would be a good idea, reduced down to a 4" round to 3x4 downspout adapter at ground level. And don't let anyone tell you the joints don't need to be glued. That's where tree roots will enter if it's not glued!!!

You can also get trash screens for your gutter outlets to prevent your pipes from getting clogged with leaves and debris.
 
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Old 06-18-19, 04:51 PM
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So my question, what size is the drain pipe?
 
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Old 06-18-19, 05:50 PM
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Gutter downspouts backing up

Thanks!!

the downspouts are 3x4.
The drain line is 4 at downspout connection, but 3 where it exits to street side.
 
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Old 06-18-19, 08:13 PM
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Pretty hard to cram 12 Sq in of water down a 3" pipe (7.07 sq in) especially if there are roots in there. That's pretty easy math.
 
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Old 06-19-19, 06:39 AM
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since the line empties into street, I'm wondering if the 'township' will have an issue with me increasing the size of the pipe.
If they do, would it be worth while to increase size of pipe where downspout enters, and gradually taper it down to the 3"?

Thanks so much for your help! I'm in uncharted territory with this subject....
 
  #7  
Old 06-19-19, 09:40 AM
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Question Rain water problems

Hello.
I am definitely a novice at this. Thanks in advance for all help.

I had new gutters and downspouts installed on my house. The new downspouts are 3x4" which are apparently 'too efficent' for the 4" drain lines they empty into. The drain lines run underground through my yard and daylight into the street. The Township where I live has a 4" maximum size limit.

During heavy rains, water will 'back up' and splash out of downspout/drain line connector. This is appears to be cause of water coming into basement through cement floor.

Help please!!


 
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Old 06-19-19, 09:43 AM
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Township has 4" restriction on drain lines.......
 
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Old 06-19-19, 10:57 AM
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If you are limited to 4" then one option is to make your 4" pipes as efficient as possible. If your pipes are currently corrugated black plastic they generate a lot of resistance and collect debris. Replacing them with smooth walled, rigid PVC will allow the water scoot through with less resistance and better flow. Also removing any sharp bends will help. If there are 90 degree fittings replacing them with two 45's will create a more gradual change of direction and allow the water to flow more quickly.
 
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Old 06-19-19, 10:59 AM
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Thanks Pilot Dane!
I have PVC currently, but I suspect 90 degree angles.
 
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Old 06-19-19, 12:10 PM
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Similar threads now merged.
 
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