Trailblazer Cargo Cover 04 CHEVY TRAILBLAZER BACK CARGO FLOOR CPMPARTMENT FILLS WITH WATER?

04 CHEVY TRAILBLAZER BACK CARGO FLOOR CPMPARTMENT FILLS WITH WATER? - trailblazer cargo cover

The rear bottom of the tank filled with water. The tailgate seal is not leaking. The soil around the tank is dry. The lid of the interior is dry. I pulled the carpet and padding and the metal is dry and the carpet was so wet just farce. It's very rare everything is dry, except in the interior of the container. It is not wet enough standing water to an inch or less. Please help.

Please only serious answers.