How to Build a Pool: Retaining Walls - Specialty Pool Products Nov 19, 2012 . Article about the types of retaining walls commonly used around swimming pools. DIY inground pools, that is! . If your yard is steep, or there is a hill or drop-off in close proximity to the pool, it will be necessary to build a retaining wall to keep water (and dirt) away from your pool. This is determined in the..