I found water dripping from the corplast only after traveling in rain. Then it's forced up into it by the truck tires and other road spray besides the rain itself. I have large mud flaps as have on all trucks that I used tow RV or boat. I still get rock dings also on the front lower half. Some of that can also happen from other traffic no matter what the TV may have.
2013 24RKSWE (27ft TT) Cougar 1/2 ton series SOLD 10-2021
2013 Ford F350 4x4 CC 6.7 engine, 8 ft bed, 3.55 rear end, lariat package
Retired from Oregon State Police in 2011 than worked another 9.5 years as a small town traffic cop:
As of 05-2020, I am all done with 39 years total police work. No more uniforms for me.