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.
