Perhaps a pool should be more than just a place to swim; it should be an experience, a visual escape, a seamless blend of water, horizon, and landscape. Maybe that’s why we are all drawn to the magic of an infinity pool or negative edge pools. So, if you’ve ever wondered how that breath-taking vanishing water effect is achieved, where the pool seems to stretch into the sky or melt into the sea, we are going to closer look at how an infinity pool works.
How Does An Infinity Edge Pool Work?
A so-called traditional pool is designed with walls and coping stones that rise above the water surface. The water stays contained, and everything is neatly defined. There’s the pool edge, deck or patio, skimmers and visible coping. If you look at an infinity pool, also commonly called an infinity-edge pool, negative edge pool, vanishing edge pool, zero edge pool or overflow pool is built to blur those boundaries.
In an infinity pool design, one or more sides of the pool have walls built at or slightly below the water level. In effect, there’s no visible lip or obstruction at that edge. There’s simply just water reaching up to the very top, creating the illusion that the pool edge disappears and the water flows on, merging with the horizon or surrounding landscape. It’s quite mesmerising to watch, isn’t it?
That alone transforms the feel of the pool. Instead of a sharp delineation between water and deck, the pool becomes about the water surface, reflection, and horizon. It’s almost as though you’re suspended between water and sky. It’s a gorgeous, almost surreal experience, especially when the pool overlooks a sea, lake, cityscape, or stunning countryside.
The Engineering Magic Behind the Illusion
Of course, this no-edge effect isn’t magic; it’s expert engineering. The basic principle is simple, but the execution requires careful planning, structural work, plumbing, and a top-quality filtration system.
Here’s how it works:
You’ll see that the wall on the vanishing side of the pool is designed so that its top is slightly lower than or exactly flush with the water surface. This means that any water above that level gently flows over the edge.
To encourage even flow, the pool is often given a subtle slope which is imperceptible to the swimmer. This directs the water toward the overflow edge. When that happens, water calmly spills over, creating a gentle, continuous waterfall effect rather than a sudden drop.
Just beyond the overflow edge, and usually slightly below or behind it, there’s a concealed trough or catch basin. When water flows over the edge, it doesn’t vanish; it just lands here. This basin collects the overflowing water silently and invisibly.
From that basin, water is pumped back into the main pool. This is usually done through a filtration system. Because of this continuous water flow and recirculation, the water quality remains high, and the water level stays constant, allowing the illusion to hold.
The structural work, plumbing, and filtration systems are hidden from view. For swimmers and onlookers, all you see is a smooth water surface that seems to extend to infinity. There are no buckets, drains, or pumps visible, just endless-looking water.
Why Infinity Pools Are Often Built with Views
An infinity pool works best when the surrounding landscape, skyline, or horizon provides a backdrop for the optical illusion. That’s why many infinity pools are perched on hillsides, a gorgeous landscape, elevated terraces, rooftops, or sloping terrain. This is where the pool edge can appear to meet distant vistas or the sky. It's the perfect visual trick, especially with larger infinity pools.
If you place a vanishing-edge pool in a completely flat backyard with no view beyond its edge, you might still get the overflow effect, but you lose much of the magic, the sense of water disappearing into the distance. That’s why site selection, orientation, sight lines, and landscaping around an infinity pool are as important as the pool itself.
What’s Different
A regular pool has defined walls and edges. Zero edge pools blur or remove them. Visually speaking, anyway.
Regular pools rely on skimmers and regular circulation. An infinite edge pool will use overflow edges, catch basins, balance tanks, and continuous recirculation to maintain that overflowing water effect.
Traditional pools are more self-contained. Infinity pools aim to merge with the landscape, skyline or horizon, giving that seamless water-to-world illusion. You don't get that with a normal pool.
Because of structural engineering, plumbing, balancing systems, sloped terrain or specific siting requirements, infinity-pool installation is often more expensive and technically demanding than installing a standard pool. This is why you often find them at more luxurious hotels.
What’s Actually Going On Below the Surface
Let’s peer under the surface at what makes an infinity pool work. Here are some of the subtle, critical components you don’t see, but which are vital for the endless-water illusion, and for safe, clean pool operation.
Weir wall & precise water-level control
The vanishing edge wall is often built so that the top of the wall is just a few millimetres (in many cases 1–3 mm) below the pool’s water level. That slight difference controls how smoothly water flows over. If it is too high, the water won’t overflow properly. Too low, and the pool might spill excessively.
Catch basin
The catch basin, balance tank or water trough is the hidden reservoir that collects overflow. It’s designed to be large enough to handle fluctuations (e.g. when many swimmers enter or exit, causing displacement, or shifts in water volume due to rain or evaporation). This basin must be carefully engineered and sized.
Recirculation plumbing & filtration
From the catch basin, the water is pumped back into the main pool, often passing through a filtration and sanitising system to maintain water quality. This cycle helps ensure crystal-clear water and continuous circulation.
Structural and geotechnical considerations
Because many infinity pools sit on slopes, hillsides, or elevated terraces, they need solid engineering: stable foundations, retaining structures, careful soil/geotech work, and durable materials. The infinity pool shell must be able to handle more than a standard pool.
Design & alignment with a view
The pool’s layout, depth, pool wall placement, and orientation must be aligned so that from the main vantage points, swimmers see water seemingly merging with the horizon and not the hidden catch basin. That’s part of the infinity pool design magic.
Why Infinity Pools Are More Than Just Magic
While the visual effect is the headline, there are practical and lifestyle benefits to an infinity pool, especially compared with a standard swimming pool.
- Because water is constantly overflowing, being collected, filtered, and recirculated, infinity pools often maintain good water quality with less visible skimmer clutter.
- Rather than dominating a yard like a boxy, standard pool, an infinity pool, when it has been designed well, becomes part of the surrounding landscape. It becomes a water feature - almost a visual extension of nature or the sky.
- Because infinity pools are often associated with luxury resorts, sweeping vistas, and high-end design, installing one can significantly elevate the appeal and value of a property or hotel stay.
- Infinity pools come in many styles. You can have single-edge, multi-edge, perimeter overflow, or even perimeter knife-edge pools for a 360° effect.
We love how infinity pools combine expert engineering and visual magic to create something truly special.