How to divert down spout water above ground to a different location

drainage

I have a down spout that exits to an area that tends to pool water. Unfortunately the flower bed area near the house is lower than the surrounding grass area – and that grass area slopes back towards the house/flower bed.

I do plan to address that slope issue eventually but wanted to divert the water coming out of the spout first. All I have read is about putting in underground drain pipes.

What if I simply just want to run it above ground, wrapping the house for about 20 feet and exiting at another area that is more properly graded? Is that not good to do?

The secondary question would be whether I would need to pay particular attention to what type of pipe I would need to use. Smaller is obviously nicer but not necessary.

Best Answer

These are the things you need to consider:

  • the pipe diameter would need to be at least the size of the downspout or larger. So we are talking three to four inch diameter. Two possibilities that come to mind are:
    • four inch diameter drain pipe with sleeve, not perforated
    • PVC pipe in four inch diameter
  • both are not pretty to look at and detract from the appearance of your house
  • in both cases you must ensure that there is a grade or drop of at least one inch over four feet. See here for details. A rough calculation for the twenty foot length indicates that the end of the drain would have to be five inches lower than the start of the drain. If you fail to have a consistent grade water will pool in the pipe and freeze in the winter. This could deform or break PVC pipe.
  • there is a risk that the pipe will not be able to accommodate the quantity of water a "once in a hundred year storm" could supply. Weather is unpredictable, if your pipe fails, then it fails next to the house. The idea of drains is to get the water away from the house as fast as possible.

So, you could do what you describe and it might work fine, or you get a bad rain storm a few years from now and have the water dumped in a window well and into your basement. Who can say?

Here are similar questions with some excellent answers. As well consider a french drain, this is an ideal solution to your problem.

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