A common question, when considering an infinity pool is about their operations. When you see an infinity pool it appears to defy the laws of nature. Therefore, it’s common to wonder how do infinity pools work?
In this article we will break down the question: how do infinity pools work? Successfully designed and built infinity pools are one of the most impressive types of pools there are. The water seems to end without a barrier. When built next to a body of water, the pool seamlessly blends into the lake or ocean. There’s not as much mystery as you might think when it comes to how infinity pools work.
How Do Infinity Pools Work?
To understand how infinity pools work, you must start to understand their components and terminology. There are largely two major differences between an infinity pool and a regular inground swimming pool. These two features are the weir wall and catch basin.
Weir Walls
The hidden wall where you see the infinity edge effect is called the weir wall. The “weir” is the very top of the wall where the infinity effect takes place. The weir wall either tilts in toward the pool, or tilts down and away from the pool.
For the most impressive infinity effect, the wall generally tilts down and away from the pool, with the high point of the weir toward the pool itself. By tilting the wall away from the pool you can create the effect of the pool ending with all but the top line of the weir wall being hidden from the naked eye. The real secret of an infinity pool is to hide the very top of the weir wall with the meniscus of water overflowing the weir wall.

Catch Basin Definition
Now, we have a weir and a pool full of water, but how do we keep the water from just splashing over and the pool’s water level going down? Well, that’s where the catch basin comes in. Below the weir wall, and generally hidden from view in a successfully designed infinity pool, will be the catch basin or catch pool where the water overflows to. The design of the catch basin is very important as you need to be able to accommodate splash out from the pool above while also being able to pump water from the catch basin to the main pool to keep the infinity effect.
How Catch Basin Returns Pool Water
Water is pumped from the catch basin to the pool. The water is typically returned to the pool through floor returns. This system is often used in competition pools. Floor returns equalize the way water is returned to the pool without disturbing the surface. In an infinity pool, these floor returns help maintain the glass-like surface of the pool while overfilling the pool just enough to maintain the meniscus on the weir wall and keep the infinity edge effect in place.
More Considerations For Asking How Do Infinity Pools Work?
There is a lot more when it comes to an infinity pool. Additional topics include debris collection methods to water level controls and disinfection. We’ll get into those topics later on, but in a nutshell, the explanation of weir wall and catch basin answer how do infinity pools work. If your questions pertain to safety, read our are infinity pools safe article for more details.