Almost any solid wall will suffice. I use the term “solid” wall because it is generally not a good idea to use a wall with windows or such – even the best players sometimes make errant kicks. Also, most chain link and iron fences can damage balls and will produce unnatural return bounces. Still, you can usually use racquetball or handball courts, wood fences (providing they do not splinter), cinder block and brick walls, and even many dirt mounds or embankments, etc.
You can also use any ground surface, though the ideal surface is grass or a surface similar to the type you normally play games on.
Wall Ball Practice Drills
Be sure to check out Part 2 for more wall ball games you can do.