Swimming sustainably

Australian homeowners have increasingly been turning to natural pools as an eco-friendly alternative to traditional swimming pools. Jacqui Hagen dives in.

The concept of ‘natural swimming’ has been getting more and more popular in recent years. Essentially, the term refers to swimming in bodies of water that are not chemically treated. The novelty can be somewhat lost on many of us living in Australia, as we’re fortunate to be surrounded by pristine waterways and beaches perfect for swimming. And yet, there’s one side of the trend that we can fully get behind: the construction of natural swimming pools as part of landscape design.

Also known as eco pools or biological pools, natural pools don’t rely on traditional chemicals like chlorine to maintain water cleanliness. Instead, they use the natural filtration power of plants, gravel, and beneficial bacteria to purify the water. With crystal-clear waters, lush plant life, and no expensive chemical upkeep, it’s hard to believe that they are not more common.

Natural pools for swimming
Natural pools for swimming are designed to mimic the water purification processes found in ponds, lakes and streams, offering an environmentally friendly alternative to chemical-based pools. The pools are typically divided into two zones: the swimming area and the filtration zone. The water in the swimming area is filtered and purified by the filtration zone, which contains aquatic plants and gravel beds that act as a biological filtration system. Plants help absorb nutrients from the water, while microorganisms living amongst the gravel break down organic matter and remove contaminants.

Phillip Johnson is an award-winning landscape designer who’s globally recognised for his natural swimming pools. Phillip looks to wild Australian landscapes to inspire his designs, creating gardens full of tumbling boulders, winding paths that blend organically into their surrounds, and pockets of indigenous plants fringing sparkling pools. I reached out to Phillip to discuss why natural pools are becoming so popular, and what people need to know when considering one.

His enthusiasm for biodiversity and natural ecosystems is infectious, as is his excitement at clients discovering the joy that comes with introducing a thriving, swimmable habitat into their backyard: “People are realising that a connection to their natural surroundings – and to beauty – is essential for their wellbeing, especially after the pandemic. Whereas traditional pools are just dead, lifeless bodies of water that offer nothing to the environment, natural pools are layered in biodiversity. It’s a real joy to see them come to life, and watch them evolve through the seasons.”

Phillip clarifies that there are some key considerations when it comes to installing a natural swimming pool. Permits and regulations must be followed just as they would be for a traditional backyard pool; this includes engineering, council permits and appropriate fencing built by a registered builder. Water storage is also very important to consider – Phillip’s designs are not connected to mains water, so the collection and storage of rainwater is a key element, ensuring the sustainability of the natural pool.

One of Phillip’s favourite recent designs is a small round pool installed in a garden in Warrandyte, Victoria. The pool, pictured opposite, has a regeneration zone and swimming zone, uses water collected onsite, and has a small trickle pump that is powered by solar panels and the house battery. Owners Mibel and Bill say that natural pools just make sense: “We love that there are no chemicals, and that it is self-sustaining. The water quality is amazing. It is crystal clear, and unlike a chemical pool, when you get out it almost feels like the water has been moisturising your skin!”

Converting existing pools
Traditional backyard pools can be converted into natural pools, though there are limitations, especially if the pool is going to be used for swimming. If the pool is old, the integrity of the shell may be compromised, especially if it has been sitting empty for a while. Plumbing infrastructure must be reworked and brought up to code before it can be used as part of a natural swimming pool. But this is a consideration rather than a barrier, and Phillip describes many projects that have successfully turned standard, chemically treated pools into freshwater swimming spots that are rich in biodiversity.

If the intention of the conversion is just to create a landscaping feature and habitat zone without the swimming, there is more flexibility, though each council will have different guidelines.

Natural pools for ecology
Natural pools can be incredibly rich habitats for native species of plants, fish, birds and insects. They can be installed in surprisingly small backyards, and are a great way to bring life into your garden. Phillip recounts stories of clients reaching out to let him know what species have arrived in their backyards: “I love getting the message from clients that frogs have arrived.”

Mibel explains that the biodiversity is one of the best things about their natural pool. While used for swimming only in the warmer months, it is a busy hub of activity all year round. She has stocked the filtration zone of their pool with three species of native fish, which are thriving – despite the watchful eye of the local kookaburras. “Every morning I visit the pool as part of my wander around the garden, and check out what’s happening,” she says. “There’s always something to observe. It has become such a big part of our life – the whole concept is wrapping itself around us in the most lovely way.”

Phillip hopes that Australians continue to embrace natural pools, and understand their value in supporting biodiversity, as well as providing a source of joy. As Mibel says: “It’s not really a pool, it’s an ecosystem. And it is teaching us so much – but instead of learning about what chemicals we need to buy from the pool shop, we’re learning about what species are arriving, and observing a rich habitat in our own backyard.”