Pelican™ Elite Coolers are not designed to be airtight or watertight. While the gasket in the cooler lid is freezer-grade, it is not intended to seal. If you tip the cooler over, then water will leak out.
Additionally, there is a small gap in the gasket that acts as a pressure release to make opening the cooler easier while it is in use. This gap also makes it safe to use dry ice within hard-sided Pelican coolers, allowing sublimating gas to escape the cooler without causing an explosion.