Overflow swimming pool design (also referred to as a knife edge swimming pool or a wet edge swimming pool) incorporates the infinity-edge look but differs in that the design allows water to spill over all four sides. Like the infinity design, the water that flows over the sides of a perimeter-overflow pool is collected in a hidden catch basin and recirculated. Some perimeter-overflow designs include elevated edges that spill into a catch basin below while other perimeter overflow designs sit the pool flush within the deck with the overflow spilling into a narrow hidden catch basin underneath.
This elegant style of swimming pool is often described as mirror-like. Perimeter-overflow allows water to pour in a thin sheet over the edges resulting in a smooth and reflective surface. While this is a stunning visual effect, construction of this type of swimming pool design is complex and requires advanced knowledge of hydraulics and swimming pool construction techniques (these hydraulic systems are a hybrid of pressurized returns and gravity drain lines).