A plastic litter box has reinforced corners with support holes for posts. Rectangular, square or triangular shapes are included. Each post has a hook. A singular piece curtain is hung on the hooks all around the inner walls of the base of the litter box. The pet entrance is left open without the curtain. The curtain hangs down about half way along the sides of the base. The base walls can extend outward at the middle and be straight sided, or can have inward slanting walls to cause a contact with the curtain and keep waste from getting behind the curtain. The base corners can be contoured to eliminate any waste buildup and facilitate cleaning.
