New swim technology is tapping into the environment’s existing methods for filtration and sustainability, creating eco-friendly pools so beautiful you’d swear mother nature built them herself. 

Americans are conditioned to think of swimming pools as man-made water dwellings, complete with blue-tinged tiles and chlorine. In Europe, however, that idea has been evolving steadily over the past couple of decades to include pools that look more like extensions of natural surroundings, adapting existing terrestrial methodology for filtration and sustainability. Simply put: Natural swimming pools (NSPs) are eco-friendly, intuitive aquatic innovations. On top of that, they’re finally traveling across the pond and into backyards in the United States.

“It’s new technology, which is why people are skeptical. It’s really the difference between sterile water and natural water,” says Alan Weene, from BioNova Natural Swimming Pools, a global network leading the charge in designing and streamlining NSPs. “Naturally existing bacteria is not necessarily something we should be killing, though. Mother Nature already knows how to purify water. Natural swimming pools are like hybrid vehicles used to be. When people started to understand them, they caught on. We expect the same thing to happen.”  

A pool built by BioNova Natural Swimming Pools at a residence on Nantucket

That understanding of NSPs will come with time, and more exposure to the technology in the U.S. Now that BioNova is working on North America’s first public natural swimming pool, to debut at Minneapolis’s Webber Park in spring 2014, don’t be shocked if NSPs catch on in eco culture. What makes them so great? The constructed pools are ecologically harmonious, enhancing nature’s design for swimming instead of developing completely new techniques, which often work against it.

All purification of NSP water is biological, meaning it’s entirely chemical-free—no chlorine, no bromine, no synthetic additions whatsoever. Here’s how the pools work instead: The water is divided into zones with specific plants in each, helping clean and maintain the pool with an optimal cocktail of microorganisms. The plants dwell in gravel, water is pumped through each of the zones, and the tiny life forms become permanent fixtures that are continually cleaning the water. Unlike a traditional swimming pool, filtration plays off the environment, involving biological elements like special grasses and reeds planted at one end of a pool. As with a regular pool, you clean surface water by hand with skimming devices.

Weene says that if you can get used to the natural look and feel of the pool, there are enormous benefits. “It’s chemical-free, so it’s healthier and safer,” he explains. “It helps restore habitats, and it’s a lot like caring for a terrestrial garden.”

That comparison means you’re likely familiar with all the NSP’s upkeep. If you’re looking to become a pool owner but don’t like the thought of maintaining a traditional pool season after season, NSPs might be your best bet. Once the pool is installed, as long as you care for the plants and use basic sediment-removal practices, the chemical-free setup is a gift. Additionally, smaller pumps use less energy, reducing the carbon footprint. And eliminating chemicals also means maintenance costs are nonexistent, whereas traditional chlorinated pools can cost hundreds or thousands of dollars per season to maintain.

“The theory of a natural pool is very appealing,” says green-clean expert Leslie Reichert, author of The Joy of Green Cleaning. “They are easier and cheaper to maintain since you don’t use any chemicals. The only real maintenance is vacuuming the sediment. They do not need to be emptied or covered in the winter, and there’s just an initial break-in time where the filtering process would remove algae and let the natural filtration take place.” After that [two-week] delay before each season, you’re free to swim.

However, the downside is you may have to get used to a different kind of swim. While natural swimming pools are pretty to look at, as they often seamlessly meld into the environment, the water isn’t the crystal-clear kind you’d find in a sterilized pool. According to Weene, NSP waters tend to be “moody.” That’s the nature of biology, so to speak. “They’re not going to look the same everyday,” Weene says. “But you will be able to see to the bottom, so that’s still okay. There’s all-natural water in there, and the appearance is telling you that something is out of whack.” Not necessarily wrong, but off—and when you notice changes, nature should make the necessary adjustments to self-correct the issue and stabilize. Cloudy water might signal excess algae growth, for instance, and the aquatic plants serve to perform necessary functions, like nutrient extraction.  

Weene insists the pools are “always safe and healthy to swim in” while the habitat returns to an even keel. However, you may have to ride out those inevitable bumps in the road. “No two pools are exactly the same,” he says. And that can be a positive. The pools are not just different in water behavior, but in look as well, so each design is unique. With NSPs, you can dream up a roadmap for any layout, depending on how exactly you’d like to use the pool and how much space you have.

Take it from Chris Rawlings, founder of Water House Pools. A graduate of the Rhode Island School of Design, Rawlings creates natural swimming pools centered around stonework. He constructs ecological wonders in the Northeast, ranging from small to large. Sometimes it’s a plunge pool for one or two people to utilize at a time; other times it’s a super-sized pool for extra functionality, like the one he created for a community-supported agriculture farm in Massachusetts that doubles as a water-retention pond. Every project is different, so prices and specifications fall everywhere across the board.

“It’s really site specific,” Rawlings says. “All my pools have had a specific set of requirements from the owners. We try to make them as energy efficient and maintenance efficient as possible, but other than that, it’s their pool. I try to include the client as much as I can in the design process, so they have a sense of ownership.” Rawlings’s designs, in particular, focus on stones, to further accentuate the natural allure of NSPs. “There’s such an energy that stones give to a constructed landscape,” he says. “It’s a real sense of timelessness, like the design has been there forever.”

So what’s not to love about natural swimming pools? “They’re not for everyone,” Rawlings admits, although he thinks they will make sense for a lot of would-be pool owners in these  more eco-friendly times.

Three Key Benefits of NSPs

Alan Weene of BioNova highlights these NSP advantages:

1. They’re chemical-free

With the natural purification, your family won’t be exposed to chemicals like they would with a traditional chlorinated pool.

2. Less energy

Lower flow rates and a lack of chemicals contribute to less energy use, helping to reduce the pool’s carbon footprint.

3. Lower maintenance

You don’t need to rely on chemicals to maintain and purify water, so taking care of the NSP is more like taking care of a garden–trim and groom plants, and get rid of debris and sediment.