Donna
Heh, I should leave that to Irene to explain. :0
Honestly, I shouldn't be weighing in because I'm really no expert, though I should be now that I'm a homeowner with a leaky basement, huh?
Here is all I know: we were told by our builder ours was a "french drain." Then the inspector said that the builder was using the term a little loosely, so I'm not sure ours fits the standard, precise technical definition, although the inspector did say whatever it was called, it was appropriate, it was designed well, and works well enough that provided we don't disturb our grading, the other half of the basement should remain water-free.
At any rate, our "french drain" is basically an area (about 8 inches in width?) all around the perimeter of the basement that has been dug out and filled with gravel. The water coming from the walls drains into this gravel and out under the basement floor, or something like that... I'm not sure where it actually does drain (it may drain out the sump pump); I just know that this gravel "moat" prevents the water from the walls from pooling and collecting in the rest of the basement.
jen
