Building a retaining wall, looks like an L from above. The block is versa lok standard 6" face and 3 tall at its tallest point where its going down the slope. 1 foot from the back fill is a pre existing draintile leading out to the yard underneath the lawn. their is no pea gracel or gravel around it. On the other side of the "L" its only 2 blocks high and 3 feet away is a patio that is mostly draining away from the wall. Do i need to do draintile for this type of wall?