We picked up an 05 roadster in the last couple months and I am just going thru it, fixes etc, The drain inside the fuel door was holding water. The car spent 9 years in California and 5 years in Arizona and probably never even saw rain before it came to Ontario. I thought maybe spider nest at the bottom of the tube.. Tried blowing some air lightly, ran a chase thru the tube. Appears there may be a kink at the bottom end. Can't easily access tube from inside convertible cover as you can't reach the bottom from the inside. Outside, bottom of tube (opening) appears to be hidden behind behind a panel on the undercarriage attached to the rear bumper cover. It initially appears a little tricky to remove. Anybody have any experience with this. I tried searching a few different ways to fix this problem and found nothing. Boy these things are well built.

 

Canada? SoCal , AZ, NV, NM & So. Utah are mostly desert except for the Pacific coast (CA) and the high elevations in both States. "Monsoon" weather can bring serious thunder storms & flash flooding, although average yearly rainfall is relatively low. Congrats on your new family member.
Definitely check your central locking pump area & fender well for evidence of water leaks. ("basement" of trunk area) Also, I think the seal for the fuel filler area is prone to water leaks, leading to the fender well & trunk? If water does enter the trunk bottom, there is no readily available drain provided. (I believe) Let us know what you find, please.