To move rainwater further away from a foundation than the standard 2~3 foot above-ground downspout extensions, what are the underground options?

Example of standard downspout extension:
Standard downspout extension
(Photo from carlsonexteriors.com)

When searching online, I see many examples of a downspout connecting to several yards/meters of flexible underground pipe which then raises to a "pop-up drain emitter". They open to allow water out, and close when the inside pressure drops, blocking water from entering from above.

Example of a pop-up drain emitter:
Pop up drain emitter
(Photo from kisseutopia.club)

Are these pop-up emitters necessary? Couldn't the underground pipe just have an open end with a grate?

I find the pop up emitters to be rather unsightly, especially next to a public sidewalk (which would be the maximum distance away from the foundation).

  • Without more info on "pop-up drain emitter", I assume that they also "seal" shut when no water is flowing, therefore allowing the water to drain in one direction, and not fill fro outside the pipe and back into the gutter system?
    – Jeff Cates
    Commented Mar 11, 2019 at 21:04
  • @JeffCates - You are correct. I have included an image. Assuming that the grade is correct, I imagine that water entering the one end would not flow back toward the foundation, but perhaps that is not the case.
    – Bort
    Commented Mar 11, 2019 at 23:52
  • That being the case. I would assume the "best" approach would be the emitter. Even if the grade is sloped properly, water could still enter, as well as any other debris that might "float" around the area. With a grate, you would need to clean it out often because of the excess debris.
    – Jeff Cates
    Commented Mar 12, 2019 at 3:50

1 Answer 1


Pop up emitters are a good thing that do a few jobs. They stop debris from falling back down into the pipe, but more importantly (in my area) they stop mosquitos from getting in and multiplying in the standing water. If a grate was in place, you have open access to standing water.

They don't have a water-tight seal so they do not really stop water from back-flowing. It's more for debris and to some it's a little "cleaner" looking than an open grate.

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