My first test print in PLA (using 0.3mm layer height) turned out to not be waterproof. Would recommend ABS for durability and maybe some coating of the inside to make it waterproof.
Will update when I've found a solution, if anyone has experience with waterproofing 3d prints please let me know in the comments.
The author remixed this model.
Increased the size and added negative modifiers to hold water.