When Denise Carroll jumps into her pond from its ledge, she swims alongside kois named Cutie, Baby and Jason (names chosen by her two young children). She’s not crazy about sharing the water with the scaled swimmers — “I’m afraid that I’m going to jump in and land on the fish” — but Ms. Carroll, who is 44 and works in biotech sales, feels that the benefits of swimming in a chlorine-free body of water surrounded by natural plants outweigh any potential ick.
After all, this pond is the swimming pool Ms. Carroll wanted, and she worked with Sarita Landscapes and California Waterscapes to build it in her San Diego backyard. She is one of an increasing number of Americans who, thanks, in part, to videos shared by sustainable living influencers on TikTok and an increasing number of companies that offer installation services, are beginning to build in their backyard the very thing that can be found naturally on many parts of the planet: a pond, or a natural pool, as it’s sometimes called.
Unlike traditional swimming pools, which contain chlorine, natural pools rely on plants and rocks for filtration instead. An underwater retaining wall separates the swimming area (where humans — and sometimes fish — swim) from the regenerative zone, which closely resembles wetlands filled with aquatic plants like water lilies or water lotus. Pumps, and sometimes waterfalls, keep the water moving, and the rocks and skimmers filter sediment and large debris.
This alternative might appeal to the environmentally minded. “Backyard ponds that don’t have chemicals in them can foster biodiversity and be important habitats for a variety of wildlife,” said Meredith Holgerson, an assistant professor of ecology and evolutionary biology at Cornell University who studies natural and human-made ponds.
The idea of a natural pool intrigued Morgan Castellow, 34, who now shares one in Moultrie, Ga., with his wife, Amanda Castellow, and their four children. “I think probably the most fun I’ve had with the pond, short of it just being beautiful to look at, is with the children,” Mr. Castellow said.
As a founder of Avery Outdoor Design, he also uses his pond as a testing ground. Working with a group of friends, and consulting with the British company Organic Pools, he built his natural pool two years ago using limestone for the retaining wall. A dock spans the wetlands, allowing swimmers to jump in. Since then, he has built another pond for a client in Thomasville, Ga.
And, of course, where there are pools, there are often parties. The Castellows recently hosted a concert for about 80 people, in which John B. Clark, a musician from Jefferson, Ga., used the deck above the pond as a stage while the audience sat around the pond.
The cost of building a natural pool is fairly comparable to that of a chlorine pool — in Southern California, Sara Bendrick, the founder of Sarita Landscapes, who worked on Ms. Carroll’s, said, it can range $50,000 to $200,000 depending on the size — but natural pools are quicker to compose. “The materials are a lot simpler,” Ms. Bendrick said.
Natural pools are considered lower maintenance, too, because owners don’t need to add chlorine once a week to the water. Other issues may arise, such as too much algae, but generally, it comes down to the plants, which can be thinned out.
There’s also the beauty. When Dr. Holgerson surveyed landowners in upstate New York about their ponds, whether they were for swimming or not, many reported feeling relaxed just looking at them. “I don’t know to what extent that’s true for a rectangle concrete pool in your backyard,” she said.
When winter comes, no closure is necessary. With the water movement, ponds tend to not fully freeze over. And it still brings joy. Ms. Carroll said that she might not swim in winter (even San Diego gets nippy), but it was still “enjoyable to look out and just feel like you’re in a little bit of nature.”
Then there are the critters the ponds attract — which can be a selling point for some. The plants surrounding a pond, and the pond itself, play host to all manner of fauna. “You can’t build one of these and not see dragonflies and minnows and tadpoles from the toads or frogs,” Mr. Castellow said. He has found snakes, and even a freshwater eel, in his pool, but the water is clear enough that he can spot animals before there’s trouble.
Mr. Castellow considers these creatures a perk, particularly with children. “I think the ability to experience nature in a very real, tangible way and see some cool ecology in your backyard is just incredibly rewarding.”