Hard rocks such as granite or river gravel prove viable options for a French drain because they won’t break down over time as much as other rock varieties, such as sandstone and limestone.Click to see full answer. Hereof, what is the best rock to use for drainage?For the best drainage, look for coarse washed rock (gravel) that is screened, with a stone size of 1/2 to 3/4 inch. Smaller rock with fine particles could clog the holes of the drain pipe. Pea stone works, but the smooth stones settle together and don’t move as much water as coarse rock.Additionally, is sand or gravel better for drainage? Sand compacts and retains moisture, therefore it does not drain as well as gravel. Although sand is not the best choice for back-filling a French drain, it does work well for some other types of drainage systems. Likewise, people ask, does gravel help with drainage? Gravel is an ideal drainage solution for two primary reasons — weight and an impenetrable surface. The weight and coverage area provided by the material prevents erosion, and its solid, moisture-resistant design allows water to drain faster. As such, it prevents precipitation from pooling on the surface.What gravel is best for driveways?Top layer choices for gravel driveways might include crushed shale, limestone, granite and concrete, along with other types of gravel in various colors to meet your aesthetic needs.