I live in Southern California, it barely rains here. However, I am working on my yard and just built a retaining wall and was required to use perforated 4" pvc pipe behind it.. Now I need to do the other part of my yard and Im wondering what's the best solution for the drainage. Can I just just use the solid pvc? HOA is requiring me to install drainage, but no requirements as to what material to use. Anybody has an advice to what's the best solution would be? 4" solid pipe? it will drain to the front yard where we are required to have pea gravel for that reason. And if solid PVC is the right material, do we need the gravel on the trench at all? Thank you.