Symbols are objects, characters, figures, or colors used to represent abstract ideas or concepts.
Chinatown, a place where secret organizations rule, the law is meaningless, and good intentions are brutally suppressed, serves as the symbol for the true nature of every city. Corruption not only exists but has become so much a part of the way societies work that even good men like Lieutenant Escobar do not attempt to fight it. Noble leadership is a lie, civic leaders like Yelburton are willing to do anything to the public in order to line their pockets, and men like Cross are above the law.
The injury Jake sustains at the reservoir serves as a symbol for Jake’s limited heroism. While the typical movie hero quickly shakes off an attack, Jake wears the marks of his injury throughout most of the film. The bandage portrays Jake as subject to human frailty and fallibility. Jake deflects questions about the injury with sarcasm, echoing the way he uses his cynicism and occasional crassness to hide his sense of decency. The scene where Jake and Evelyn sleep together begins with Evelyn tending his injury, suggesting that this sign of weakness is in fact what makes Jake appealing.
The saltwater pond serves as a symbol of the inherent duality of human existence. On one level, the saltwater pool found in the Mulwrays’ back yard is a source of life, a duplicate of an ocean tidal pool that supports a variety of plants and creatures. On another level, the pool brings about death, slowly seeping outward to poison the surrounding grass and any other plant incapable of tolerating the salt. The pool was also used to bring about a much quicker death when Noah Cross drowned Hollis Mulwray in it, filling Hollis’s lungs with the deadly salt water. The duality inherent in the water serves as a symbol for corruption, showing it both as the means by which a city lives and grows and as a spreading disease that taints everything it comes in contact with. Like the grass, anything that cannot adapt to the corrupt environment is eventually destroyed.