The Devil's Well is based on an urban legend called The Well to Hell. It revolves around a drilling team that tunneled deep into the earth's crust and using a fictional heat-resistant microphone, were able to capture sounds of purported screams of torture and torment emanating from Hell itself. This audio clip can actually be heard today, however it is simply a clip taken from an old movie and given new context. The Devil's Well plays a similar sounding clip near the beginning of the film.
According to director Kurtis Spieler, some of the scenes where strange sounds were heard were unplanned. Spieler encouraged the actors to stay in character if anything happened and to try and use it. As a result, the reactions by the actors in some scenes are real. In fact, the scene in which Riley and Kris are investigating the generator room and the EMF detector goes off was also unplanned. According to Spieler, the EMF detector started beeping and flashing on its own and the actors reactions are all real (while still staying in character). As a result, it became one of Spieler's favorite scenes.
The character of Kurt Schafer can be seen wearing a shirt with the name/logo "The Dick Punchers". This is a reference to Kurtis Spieler's first feature "Sheep Skin", in which the main characters are in a punk band called "The Dick Punchers".
The original title for the movie was "The Unexplained Disappearance of Karla Marks". The title was later changed to the "The Devil's Well" after the movie was picked up for distribution.