# Drainage Rocks?



## Daniel Holzman (Mar 10, 2009)

The term "drainage rock" must be local to your area, I have never heard of it before. A rock does not by definition create any drainage, at best a pile of rocks will be more permeable than an equivalent pile of clay or silty soil. However, if you purchased a house with a perimeter drain, you would probably find that the drain included a perforated pipe buried at approximately the level of the top of footer (slightly lower than the basement), and the pipes would probably be covered with crushed stone or crushed rock.

The purpose of the perimeter drain is to intercept groundwater, direct it into a pipe, and allow the pipe to carry the groundwater off to a safe location, hopefully well away from your house.

A pile of rocks such as you describe is probably there because the contractor who built your foundation did not want to haul the rocks too far away, so they dumped them near the foundation. Not for drainage, but for convenience. I have seen this many times, for rocks, stumps, even garbage. Nothing to do with drainage.

As for removing the rocks, if you don't like them, you could remove the rocks and backfill with soil, then seed and loam. Removing the rocks is unlikely to change anything about the drainage pattern near your house, make sure that you grade away from the foundation, and your gutters drain well away from the house.


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## Katigan (Apr 15, 2010)

Thanks so much! 
People use a lot of rocks around here to direct water (like a dry riverbed). Anywhere you dig, you're likely to find big softball-sized rocks, so what you said is probably the case. I just wanted to make sure that this wasn't some "technique" that I would ruin by digging up the rocks. I live on the side of a mountain and a stream runs around my house, so drainage is important. Thank you again!


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## handy man88 (Jan 23, 2007)

Katigan said:


> Thanks so much!
> People use a lot of rocks around here to direct water (like a dry riverbed). Anywhere you dig, you're likely to find big softball-sized rocks, so what you said is probably the case. I just wanted to make sure that this wasn't some "technique" that I would ruin by digging up the rocks. I live on the side of a mountain and a stream runs around my house, so drainage is important. Thank you again!


The purpose of these rocks is probably to hold the ground in place. With the rocks, the dirt is less likely to wash out as it absorbs the impact of the water falling on it.

Rocks used to hold the ground firm is usually called "rip rap."

http://en.wikipedia.org/wiki/Riprap

It would also help if you posted picture of what you have.


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