To my knowledge Kansas or at least my region does not require flood testing nor did Savannah GA when I Operated there for six years. Maybe stricter codes would help keep "fly by night" installers out of business! I still strongly believe in a pre slope underneath a shower pan liner with a mud bed on top. No Styrofoam! I also like to waterproof the mud bed and my walls. There are so many extras you can do and techniques to ensure your installation is tighter than a bullfrogs butt! Unfortunately the basic knowledge of construction and water flow has seemed to bypass a huge chunk of our industry.