The quote "It's like I was connected to the plumbing system" from Rick Riordan's "The Lightning Thief" reflects a character's newfound understanding or ability. It suggests a sense of belonging or access to a deeper network of connections, akin to how plumbing systems provide essential support and communication within a structure.

This metaphor highlights the character's realization of their unique powers or status, emphasizing the bond they share with their environment and the elements around them. It also echoes the larger themes of discovery and identity that are central to the story, where characters learn about their heritage and capabilities.