Caves

The inside of a dungeon.

A Mosasaurus patrols an underwater cave.

There are caves and dungeons that connect the ocean to freshwater lakes and temples.

These caves can be explored by aquatic and semiaquatic creatures, such as Ichthyovenator, Mosasaurus, Elasmosaurus, and Kronosaurus. This way they can get from the sea into the lakes. Therefore, not even freshwater lakes and pools are completely safe to drink from, and one must be vigilant before getting close to drink.