Need help on a customers yard. They live at the bottom of a small hill with houses atop the hill. The yards are 1/2 acre lots in a small neighborhood. The problem is the water is drifting downward and possibly causing saturated ground in their lot. They have lived here since 1977 and seems to be getting worse. They had to move their septic tanks to the front yard because their toilets would not flush during hard rains. The front yard now seems to be the worse. The grass is slowly thinning out and dying. the front yard stays saturated with very little saturation in the back yard which faces the uphill. They have neighbors on both sides of their house. There is a shallow gulley between the yards but that has since become even more shallower. Should I start by digging a deeper gulley for better drainage which leads to the ditch or is it possible there may be a leak in their spetic tanks or all together another issue? Thanks for any assistance.