We are having a new driveway poured. As preparation for this, and to help pull water from the foudnation, we want to connect the 4 or 6 if possible downspouts to an existing drain line that runs the length of our lot (approx 90') To set the image: The existing 4" thin wall drain line is on the far end of the driveway - going parallel to the drive. The house and downspouts are across the drive (approx 13') We are in Houston, TX - so not a ton of rain here - assuming we don't get any hurricanes. Questions: can we connect 4-6 downspouts to a 4" drain line. We have dug a trenc - getting the slope is what is proving challenging. Do you suggest starting at the highest point in the run or the lowest and working bckward? Beside the 4" pipe we are running 2 - 3/4" electrical condiuits the length of the drive. We have our trench approximately 6" wide. Once the pipe is in there, is it sufficient to fill the trench just with the dirt we removed, taking care to compact it? Or do we need rock? Should we be putting the pipe on a bed of rock/gravel etc.? We are planning for the top of the pipe to be a minimum of 9" from the top of the anticipated concrete. Is that sufficient to avoid cracking of the driveway? Lots of questions, thanks for answering whatever ones you can. We have spent a couple days out there, adjusting thingns alot. Your help is appreciated.