Water is a key motif in the novel, introduced by the flashforwards to the murder scene describing a body floating in the lake. The teens regularly gather at a local swimming hole, while the pond on the Swift property is both the site of Jackson and Ethan’s tryst and the location where Jackson catches Abigail and Alexander together. The motif of these bodies of water reflects hidden depths and dangers lurking below the surface. Bodies of water can seem innocuous and pleasant, but it can be hard to accurately distinguish what lies underneath. The attempt to hide the corpse by sinking it in the lake establishes the connection between bodies of water and The Deceptive Nature of Appearances.

What is hidden below the water can either reveal past events or active, present dangers. Blair is seriously injured after leaping into a body of water without understanding what lies in wait for her; the risks lurking under depths reflect the novel’s exploration of many secrets being concealed under the seemingly perfect façade of small-town life. The idea of hidden dangers also reflects the capacity for violence and betrayal hidden within a character’s own nature. Nellie’s capacity to kill, for example, emerges suddenly by the lake when she is provoked by Charleigh, and Charleigh refuses to be honest about her own simmering beliefs that Nellie is capable of seriously harming someone.