# French drain depth



## Mark2 (Jun 3, 2021)

What's the optimal depth for a French drain? Or to put it another way, how much topsoil do I need on top of it to be able to sustain healthy turf? It will be under 100% KBG. Obviously I want it to be able to drain well and do its job, but I also don't want the grass to have shallow roots and struggle considerably more than the rest of the yard.

I'm planning to use the NDS EZ Drain French pipe that comes premade with the fabric & poly-rock. I was thinking 6" of topsoil on top.


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## Joeeeekkkkk (Jan 28, 2021)

Mark2 said:


> What's the optimal depth for a French drain? Or to put it another way, how much topsoil do I need on top of it to be able to sustain healthy turf? It will be under 100% KBG. Obviously I want it to be able to drain well and do its job, but I also don't want the grass to have shallow roots and struggle considerably more than the rest of the yard.
> 
> I'm planning to use the NDS EZ Drain French pipe that comes premade with the fabric & poly-rock. I was thinking 6" of topsoil on top.


Not sure it'd be much of a difference, but I buried three downspouts this past winter when my lawn was dormant (Georgia). I would guess there was 6-8 inches of top soil on top of 4" PVC and some rocks I threw around the pipe that I had no was to dispose of.

When I dug the trenches I tried to cut perfect pieces of turf so I could lay them back over the backfill. Aside from a slight leveling issue, the grass is no worse for wear and most people would have no idea the drains are even there. I think 6-8" should be fine but I'm no expert and also different turf.


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