A puddle flange is a ring-shaped component installed around a pipe that penetrates a concrete wall, floor, or tank to create a permanent, mechanical barrier against water leakage. Unlike pipe flanges, a puddle flange’s purpose is not connection, but to ensure a watertight seal by preventing water from traveling along the external surface of the pipe into the concrete. They are essential in structures like basements, tunnels, water tanks, and manholes, where water damage is a critical concern.