GITTES: Look, pal—I make an honest living. People don't come to me unless they're miserable and I help 'em out of a bad situation. I don't kick them out of their homes like you jerks who work in the bank.
Jake is defensive about his work. He knows how it looks to some people—like he's breaking up marriages—and it's important to him that he believes in the fundamentally moral nature of the work he's doing.
EVELYN: Whoever's behind my husband's death, why have they gone to all this trouble?
GITTES: Money. How they plan to make it by emptying the reservoirs—that I don't know.
Money is the "root of all evil." But it's apparently worth a murder and worsening drought…at least in the eyes of the bad guys.
GITTES: Did you know that you're a very wealthy woman?
EMMA: I'm not!
Emma is being unwittingly exploited. She seems to be leading a fairly happy life at this retirement home, but she's actually being used to further the greedy designs of Noah Cross. Noah is buying land under her name and those of the other residents, and transporting the stolen water to their property.
EMMA: No—the albacore. It's a fish. My grandson's a member—and they take very nice care of us.
GITTES: How do they do that?
EMMA: Give us things—not just some old flag like this, but—
GITTES: But what?
PALMER: We're a sort of unofficial charity of theirs, Mr. Gittes. Would you care to come this way? Someone wants to see you.
Noah Cross is a member of the Albacore Club and this detail points out that he's one of the culprits behind the water-stealing scheme. Albacore was also the word misheard by Jake's assistant Walsh as "apple-core."
GITTES: I want to know what you're worth—over ten million?
CROSS: Oh, my, yes.
GITTES: Then why are you doing it? How much better can you eat? What can you buy that you can't already afford?
CROSS: The future, Mr. Gittes—the future.
Cross's greed isn't just about satisfying his appetites. It's about the pleasure of control—not just control over his family members and the present population, but of future generations.
GITTES: He's rich! Do you understand? He thinks he can get away with anything.
In the end, we realize Noah doesn't just think he can get away with anything—he knows it.