Cool Pools

These natural swimming pools are stunning and eco-friendly.

Imagine taking a dip in a crystal-clear Alpine lake with water so naturally clean you can drink it. Now imagine that lake—on a smaller scale—in your backyard. That’s the theory behind so-called natural swimming pools, which use nature to maintain water purity without the use of any chemicals. Developed in Australia and Germany in the 1980s, natural swimming pools include a shallow area, sometimes called a bog, containing aquatic plants that filter the water, which may also pass through a UV-light sterilization system, back into the swimming area.

Although many natural swimming pools are built to resemble ponds, with uneven, rocky and plant-filled edges, they are constructed of concrete or other lining material using the same methods as a conventional pool. In fact, they needn’t be naturalistic in design at all. A modern, rectilinear pool might be connected—by a trough or even underground pipes if desired—to a “regeneration zone” planted with cannas, dwarf horsetail, watercress, pennywort, rushes and umbrella palms. The result is a gorgeous garden that attracts wildlife and beneficial insects.

Although natural swimming pools are well established in Europe, with British companies such as Clear Water Revival and GartenART, along with designers including Michael Littlewood, a few companies have established beachheads in the U.S. The largest of these is BioNova, which licenses its technology to local contractors. Others include Total Habitat in Kansas, Idaho-based Whole Water Systems and California’s Expanding Horizons.

If going all natural is a bit too extreme for you, there are still a few chlorine alternatives available. A company called TechnoPure offers alternative pool systems that treat water by pumping it through a chamber containing coated titanium plates and copper and zinc ions, while DEL Ozone makes ozone injectors that can reduce the need for chlorine up to 90 percent—there's even one installed at the White House.