The central tension is created by Margaret, once a lover of the narrator, and inBOIL, a rebellious man who has left iDEATH to live near a shunned area called the Forgotten Works, a huge trash heap where the remnants of a former civilization lie abandoned in great piles.

In the violent climax of the novel, told in retrospect after the fact, inBOIL returns to the community along with a handful of followers, planning, he says, to show the residents what iDEATH really is.

Viewing this book, then, as a parody of the pastoral, one might consider the ideas that are implied by the silence and attempt to determine what Brautigan's attitude is toward this "perfect" society.

[5]In Watermelon Sugar is referenced in Ray Mungo's book on his experiences founding and running the Total Loss Farm commune in Vermont.

Stephen Gaskin, who wrote that he felt an "acid weird" and "strange mythology" in the book,[7] may have based some aspects of The Farm commune in Summertown, Tennessee on iDEATH.

Neko Case references this book as the inspiration for her song "Margaret versus Pauline" on the album Fox Confessor Brings the Flood.

In Watermelon Sugar is also referenced multiple times in the Dean Koontz novel, One Door Away from Heaven, by an important secondary character who believes, in her near-constant drug-soaked haze, that she would unlock the secrets of the universe if she could only understand this book properly.

Harry Styles shared, during a February 2020 Tiny Desk Concert, that a copy of the book inspired the title of his song "Watermelon Sugar".