Already ideal for alfresco dining, the patio behind the Seattle home of Jennifer Chayes and Christian Borgs lacked one element the owners wanted: a spa. To build it, they hired landscape designer and contractor Hendrikus Schraven ( www.hendrikus.com or 425/392-9977), based in Issaquah, Washington. While Schraven was planning the job, Borgs came up with another idea: converting a soil-filled brick planter along one side of the patio into a raised water garden. So Schraven sealed the inside of the planter's brick shell with concrete to form an 18-inch-deep pond.

A small recirculating pump keeps the water moving, while plants and a few goldfish keep it clean; the fish also eat mosquito larvae. Lilies grow in submerged plastic pots whose tops are 8 inches below the surface. Among the other aquatic plants suitable for relatively shallow ponds like this are American lotus (Nelumbo lutea), dwarf forms of Indian or Chinese lotus (Nelumbo nucifera), and hardy water lilies (Nymphaea species).

Schraven capped the pond with granite that matches the stone facing on the spa, which is out of sight.