This is a follow-up question to Sloping ditch for corrugated pipe

The water coming down the gutter drain has a nominal velocity and will collect and transfer to an 80 ft run of corrugated pipe (to be installed). Assuming that the pipe is perfectly level until the very end where it slopes downward into the 25 ft section (see photo in link).

  1. Will a siphon effect 'pull' the water along the 80 ft run into the 25 ft section?
  2. What is the penalty / consequence if water is not completely eliminated from the pipe and sits in the pipe until the next rainfall?

Assume a Florida venue: freezing is not a concern.

I realize that a nominal slope is the key to forcing the water naturally from the drain to its target destination, however, the question is posed to understanding the worst-case dynamics. Unfortunately, I think there is only 10 of depth available for the 80 foot run. As much as I like the idea of a column of water pressure pushing the water through the 80 foot run, I think that would require a watertight seal, which is not long-term reliable.

  • I think there is only 10 of depth available - 10 what? feet? inches? millimeters?
    – yoozer8
    Commented Sep 1, 2020 at 15:17
  • " Corrugated" sound like galvanized sheet steel . If so, it will corrode fairly fast if constantly wet. Commented Sep 1, 2020 at 16:20

1 Answer 1


You will not have a siphoning effect unless the corrugated pipe is completely filled with water and no air is allowed to enter it, which will not happen from a gutter draining into it. No real consequences of the water sitting there. Most of the water will drain out if the pipe is perfectly level, which will be hard to do. The remaining water will be the amount that is "held in place" by the corrugated part of the piping. There will be some air flow from the gutter through the pipe so the water will probably evaporate.

  • In Florida, I would think the frequency of rain would not allow the corrugated parts to dry and that would be a mosquito breeding ground. Even with a slope, I think it would be problematic for mosquitoes. Commented Sep 1, 2020 at 14:23
  • @UnhandledExcepSean The pipe will be buried so no different than a sprinkler system or plumbing for a pool.
    – JACK
    Commented Sep 1, 2020 at 14:27

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