To remove the waterproofing popup messages without rooting:
(assuming your S5 variant doesn't have the do-no-show tickboxes)
Install a custom recovery ( I use TWRP ). You will need to connect the S5 to a PC which has USB drivers installed and use Odin to install the TWRP recovery.
Once installed, power down and boot into TWRP (power, vol+, home)
In TWRP, mount /system with read-only unticked
cd into /system/app/PopupuiReceiver_M
Rename the file PopupuiReceiver_M.apk to some other extension, such as PopupuiReceiver_M.apk.disable
reboot (maybe twice)
You might get the green-and-gears screen on reboot.
You can remove TWRP when you've finished or leave it, or it might get overwritten anyway.
Another way is to trick the phone into thinking it's a VZW variant by editing build.prop, but that needs TWRP also