Most downspout drains are installed with either 4” corrugated solid pipe or 4” solid PVC pipe. We like to run our downspout drains from the furthest back downspout all the way to the street, as the downspouts connecting along the way will help with constant flow. We also like to run the drain through the lowest parts of the yard and install inline catch basins to catch any other rain water that might gather on the surface of the ground. These systems are very versatile and rather simple too.