What is a natural swimming pool?
Natural swimming pools
A natural swimming pool is a swimming pool that keeps its water clean using biological filtration and circulation rather than relying on chlorine or other chemical disinfectants.
The result is a pool that looks and feels like a swimming pool, but works more like a small, carefully engineered ecosystem.
How does it work?
A natural swimming pool has two connected areas: the swimming zone and a filtration or regeneration zone.
Water is continuously circulated between them. A pump draws water from the swimming zone and moves it through a filtration system and, depending on the design, a planted regeneration area. The cleaned water then returns to the pool.
The regeneration zone contains specially selected substrates and aquatic plants. As water passes through this biological filter, microorganisms living on the surface of the filter media break down organic pollutants and nutrients. Plants also take up nutrients such as nitrogen and phosphorus, helping to limit the conditions that allow algae to proliferate.
Mechanical filtration can be used alongside the biological system to remove physical particles such as leaves, pollen and suspended sediment. Good circulation is essential: it prevents stagnant areas, distributes oxygen and continuously moves impurities towards the filtration system.
The whole system is therefore designed around a simple principle:
move the water, remove the particles, process the nutrients and return clean water to the pool.
Natural doesn't mean unengineered
This is perhaps the most important thing to understand.
A natural swimming pool isn't clean because nature is somehow left to take care of itself. It is clean because the natural processes are deliberately designed and controlled.
The quality of the finished pool depends on getting the fundamentals right: hydraulic flow, filtration capacity, circulation, oxygen availability, nutrient management, plant selection and ongoing maintenance.
Done properly, the result is a pool with crystal-clear water, a natural character and sophisticated engineering beneath the surface.
It is swimming water designed to work with nature, rather than against it.
What makes it different from a conventional pool?
A conventional swimming pool generally depends on chemical treatment—most commonly chlorine—to control microorganisms in the water. Chlorine is effective because it is an oxidising disinfectant: it reacts with organic material and microorganisms to keep the water microbiologically safe.
A natural swimming pool takes a different approach. Instead of making the water chemically hostile to microorganisms, it uses physical filtration, biological processes, circulation and carefully controlled nutrient levels to create clear swimming water.
This doesn't mean that a natural pool is simply a pond with a swimming area. A well-designed system is a piece of engineered water infrastructure. The size and configuration of the filtration system, circulation rate, hydraulic design, filter media, planting and expected bathing load all affect how the pool performs.
Why choose natural?
The most obvious difference is the experience of the water.
Without routine chlorine treatment, there is no strong chlorine smell and no need to maintain a chemically treated swimming environment. The water can feel softer and more natural, while the surrounding planting and landscape create a setting that changes with the seasons.
There is also a different relationship with the landscape. Rather than treating the pool as an isolated, chemically controlled object, a natural swimming pool can be designed as part of the garden—with water, planting, stone and landscape working together.
And because the system is based on continuous biological filtration rather than simply adding chemicals, the pool can become a living part of the landscape rather than just a body of treated water.