French Drain - PVC holes up or down?

Old 04-29-10, 12:20 PM
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French Drain - PVC holes up or down?

In past French drains I've used the flexible corrugated black drain pipe. This time I'm using 4" PVC in case it needs to be snaked for cleaning someday. The black stuff had 360 degrees of holes, but the PVC holes are on one side of the pipe, more or less. I know the holes would orient down if I was building a leech field. But my drain intends to move water from above pipe depth, out of that area to a common dump point. My gut tells me to put the holes up, and then the higher water gets in easy, and rides the closed bottom of the drain pump toward the exit. But I read somewhere that the holes should go down. Of course, it will be covered with landsacpe cloth regardless. Any ideas?


Old 04-29-10, 04:19 PM
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The holes definitely go on the bottom (4:00 and 8:00) with proper backfill below.

This prevents soil from above getting in and minimizes the amount of silt.

Any drain pipe should be put in a perforated sock because most backfills are not graded right. Clean rock is too coarse and silt can come through it too easily.

Old 05-07-10, 08:35 AM
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I consider the sock to be optional. I have been to several drainage seminars and many think that the sock will grow algae over time that will seal off the drain.
Old 05-07-10, 08:49 AM
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I believe algae needs sunlight to grow.

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