Wells are sites where natural ground water is connected to the surface so that it may be accessed and used. Wells are especially important in desert regions or other arid areas where water may be hard to find. Fictional wells may connect to extensive cave systems below, underground lakes, underground rivers, or the sewer system. In fantasy worlds, wells may be magical themselves, granting wishes or acting like portals to another place or realm. Wells may be enclosed within a wellhouse. They are a related element to cisterns.

When designing wells consider how deep they go, how accessible water is in the surrounding area, and whether the well is full or empty. Fictional wells often connect the surface world to a strange underground realm, acting as a portal, doorway, or transition point between these locations. This can provide worldbuilders an opportunity to explore what secrets lay buried beneath the surface. Wells may open into natural terrain features such as large cave systems, underground lakes, or underground rivers, or may have been built upon man-made (or other-made) ruins, vessels, sewer systems, or other elements.

Wells, if contaminated, may spread disease.

Wells are frequently used as symbols of depth, both physical and metaphorical. Characters may descend into wells, encountering challenges or revelations that mirror their internal struggles or personal growth. The descent becomes a metaphorical journey into the depths of the human psyche. Wells are also commonly employed in horror genres to evoke a sense of dread and the unknown. Their dark, confined spaces make them ideal settings for suspenseful and terrifying scenarios where they often act to entrap characters in a similar fashion to an oubliette. The well can serve as a portal to the supernatural or as a hiding place for malevolent entities.