I am considering extending/connecting the downspouts of my house to some pvc piping which I will run underground. What are things that I need to keep in mind?

Specifically, I have the pvc piping but the joints I have are for 90 degree angles. Is it essential that they be at 45 degree instead?

Also, is it essential that the pvc piping be sloped down an inch or two for every length of pipe (in other words whats the difference if they are just level, wont the water run off anyways)?

Can I dig the trench and put the drainage piping next to the house or is it essential that the drain pipes be a couple feet away from the house as suggested by This Old House.

I live in the northeast where winters stay below freezing for several weeks (sometimes a couple months) of the year.

  • where are you going to run it to? – Steven Nov 21 '12 at 16:22
  • it will come out onto the grass about 10-20 yards from the house – n00b Nov 21 '12 at 16:57
  • a slope is rather important especially to prevent build up of leaves and dirt and the like. – DA01 Nov 21 '12 at 17:20
  • @Droid is your lawn sloped? otherwise how would you run the drain with a slope away from your house and then have it come up to drain? – Steven Nov 21 '12 at 18:02
  • yes, the lawn is sloped. – n00b Nov 21 '12 at 18:12

45 degree bends make the pipe easier to snake out if it becomes clogged. This can definitely save you a headache in the future.

Some suggest using a catchbasin with a grate below each downspout rather than connecting the downspouts directly to the underground pipe. This gives one last chance to keep leaves and dirt out of the underground piping.

Slope is definitely important for proper drainage.

As far as distance from the foundation, if you choose to use non-perforated pipe, I suppose you could run them closer to your foundation, but I'd avoid it if possible.

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  • 1
    A reasonable alternative to 45 ells are long sweep drain and waste 90 degree ells. – bcworkz Nov 21 '12 at 19:18

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