Shot in only 14 days in multiple locations.
According to an interview with 1428 Elm, director Matt Eskandari said the film stemmed from his own fear of pools and oceans by saying: "Pools and oceans all trigger a bona fide sense of dread for me. Just the whole idea of being trapped in a pool makes me sweat. I decided to tap into that fear and the concept blossomed from there."
The character played by Tobin Bell is named McGradey after the former caretaker from the director, Matt Eskandari's favorite horror film, "The Shining."
The public pool in the film is called the Ketea Aquatic Center named after the monsters of the sea in Greek mythology, the two greatest of which were famously slain by Perseus in Aithiopia and Herakles at Troy.
Jonna is named as an homage to Jonah from the Old Testament a character who is trapped in the belly of a whale.