Conspiracy
Conspiracy—the secret planning by a group to do something unlawful or harmful—is a major theme in Chinatown. Inspired by the backhanded deal-making and sabotage that arose during the real-life California Water Wars, the film depicts Jake Gittes stumbling across a high-level conspiracy in which Water Department officials and private citizens working for Noah Cross collude to create a false drought, build an unnecessary dam, and to push farmers off their land to incorporate the land into the City of Los Angeles. When people such as Hollis Mulwray threaten to expose the plan, murder becomes a necessary component of keeping the conspiracy going. While Jake discovers what Noah Cross is up to, ultimately Jake must accept that Noah's influence is so vast that he is immune from prosecution. In this way, the conspiracy is so well-integrated into Los Angeles society that it is nearly impossible to stop.
Water Rights
The issue of water rights is another major theme in Chinatown. Set in Los Angeles amid a drought, the film takes inspiration from the real-life problem of a rapidly growing population demanding more water than the natural water table or rainfall in the area can provide. To meet the city's growing needs in the early 1900s, officials like William Mulholland covertly bought up farmland outside the city limits in order to build a controversial aqueduct that diverted river water toward LA. In the film, Jake learns that Noah Cross and Hollis Mulwray's business partnership ended in part because Hollis believed the city's water should be a public a resource while Noah wished to continue to profit from it. Continuing to exert influence, Noah uses his money and power to manufacture a drought by secretly dumping water from reservoirs. In doing so, Noah tricks the public into believing the city needs the new dam project he hopes to build. Noah also sends people to poison water wells and blow up reservoirs on valley farmland he is purchasing cheaply with an aim to turn a future profit. Although Hollis learns of Noah's plan, Noah murders Hollis, ensuring that he can continue manipulating what is supposedly a public resource for private gain.
Deceit
Another major theme in Chinatown is deceit—the practice of misrepresenting or concealing the truth in order to deceive others. As a private investigator, Jake Gittes's professional responsibility is to uncover truths that people go to great lengths to conceal. While Jake's work usually involves gathering evidence of cheating spouses, the film depicts him becoming embroiled in a dense web of deceit. The theme arises early in the film when Ida Sessions poses as Evelyn Mulwray to hire Jake for what he believes is a straightforward job. Jake continues to encounter deceit, next from the real Evelyn, who hides the truth about Hollis's supposed mistress (her daughter and sister, Katherine). Mr. Yelburton, acting head of the Water Department, also hides the truth from Jake, concealing the extent to which Noah Cross continues to wield power over the city's water. Meanwhile, Jake employs his own brand of deceit to gather information, posing as people he isn't and pretending to have meetings arranged to gain access to various private offices. Jake's first meeting with Noah is also shrouded in deceit, as Noah offers him double his usual fee if Jake can bring him Katherine, who Noah pretends is Hollis's girlfriend rather than the daughter he hopes to reconnect with. By the end of the film, Jake learns the truth behind an incredible amount of deceit, most of which stems from Noah Cross's influence. However, Jake must accept that he is powerless to expose Noah, whose money and power have made it so that too many people are implicated.
Intimidation
Alongside the themes of conspiracy and deceit is intimidation. Defined as the action of frightening, threatening, or overawing someone, intimidation first arises in Chinatown when Jake is accosted by Claude Mulvihill and his knife-wielding henchman at the Oak Pass Reservoir. Supposedly working for the Water Department to investigate security threats, Mulvihill acts more like a gangster, holding Jake's arms as the henchman slices Jake's nose as a warning to keep it out of other people's business. The theme also comes up when Ida Sessions phones Jake and refuses to name the person who hired her to pose as Evelyn for fear of retaliation. Jake encounters Mulvihill again while investigating the oblivious landowners at the Mar Vista rest home, and a gun falls from Mulvihill's jacket during their scuffle, suggesting that Mulvihill might have been preparing to kill Jake. Additionally, two more henchman approach, firing guns at Jake and Evelyn as they drive away. Polanski continues building on the theme of intimidation with the revelation that Ida has been murdered by whoever hired her to pose as Evelyn—an implicit warning to Jake to stay out of the matter. The theme comes to a head when Mulvihill, at Noah's command, holds Jake at gunpoint and forces him to bring them to Katherine and Evelyn. Outside 1712 Alameda, Noah continues to intimidate, refusing to back down from approaching Katherine even as Evelyn aims a pistol at him before the police, who Noah "owns." Ultimately, Noah succeeds in overawing Evelyn and Jake, as Noah knows too many people are under his control for him ever to face justice.
Investigation
A film with a private eye as its protagonist, Chinatown is centered on the theme of investigation. Defined as the systematic or formal inquiry and examination of facts to establish the truth, investigation is established as a theme in the opening shots of the film, which focus on Jake's client looking through photographic evidence of his wife having sex with another man. Polanski builds on the theme as he depicts the methods Jake and his operatives employ when following Hollis Mulwray. While the job of a private investigator largely entails observing a subject, Jake and his men also ingeniously stick pocket watches under Hollis's car tires to establish how late he stays at various reservoirs and outflow pipes. Unbeknownst to Jake, Hollis is conducting his own investigation into the covert dumping of public water. As the film develops, Jake cannot help but continue to investigate the conspiracy he is uncovering, motivated to discover the truth despite the risks wrapped up in his investigation.
Trauma
From the Greek word for "wound," trauma—long-term neurosis that follows a deeply disturbing experience—is another key theme in Chinatown. Polanski addresses the theme most explicitly in Jake and Evelyn's post-coital scene. Smoking cigarettes in bed together, the characters discuss Jake's troubled history with Chinatown, where he was working for the District Attorney. Speaking cryptically, Jake references the lasting trauma of having tried to help a woman whose harm he unwittingly "guaranteed." The theme next arises when Evelyn confesses she has been concealing the trauma of having given birth as a teenager to a child she conceived with Noah, her own father. With this revelation, Jake realizes Evelyn's evasiveness and deceit are defense mechanisms bound up with the shame of her trauma. With Evelyn's death and Katherine being taken into Noah's care, the film ends with Jake reopening the wound of the last time he was in Chinatown. Once again, his attempt to protect a woman has guaranteed her harm.
Powerlessness
Defined as a lack of power, influence, or ability, powerlessness is a crucial theme in Chinatown. Faced with widespread corruption and duplicity, Jake tries to uncover the truth of Noah Cross's conspiracy to further enrich himself and his cronies at the expense of helpless common people. Simultaneously, Evelyn hopes to escape her abusive, murderous father and start a new life with her daughter in Mexico, far from Noah's influence. By the end of the film, Polanski makes clear that Jake, despite his tenacity and best intentions, is powerless to bring Noah to justice because Noah holds too much sway within the system as it stands. Evelyn's effort to separate herself from her father and protect her daughter also fails when her escape attempt leaves her dead and Katherine with no guardian besides Noah. Polanski captures the theme of powerlessness in the film's iconic closing line, as Walsh says, "Forget it, Jake. It's Chinatown." With this statement, Walsh is suggesting to Jake that, as with the last time he was in Chinatown, he is powerless to correct what has happened.
