The town grew up around Soap Lake, a mineralized lake—southernmost in a string of lakes along Grand Coulee—whose contents froth up in the wind like soap suds and where people come to soak for health and relaxation. Claims that the water contained more than 20 minerals have drawn visitors from the early days. The Inn at Soap Lake has operated since 1915 and there are two public beaches.
The town began as a health resort on the shores of Soap Lake; irrigation from the Grand Coulee Dam has helped it to flourish with increased farming. The lake clearly shows its volcanic origin in the cliffs of black basalt along the shore and in the accumulated minerals and salts. This mineralization gives the water its therapeutic value, and also accounts for the suds-like froth that is frequently piled up along the shores by the wind. The town is dependent on the lake for existence. Hotels and sanitariums along both the main and the side streets advertise hot and cold salt-water baths, blanket treatments, and mud baths. Facilities for outdoor bathing are available along the lake shore. During the summer months most of the inhabitants, residents and visitors alike, lounge about in scanty attire, and are so bronzed by the intense sunlight that they resemble the aborigines, who years ago recognized the health-giving propensities of the water, which they called the Witch Doctor. Though only a few hotels remain today, Soap Lake continues to attract visitors who come to its two public beaches. Soap Lake Natural Spa and Resort is comprised of several buildings: the historic Inn at Soap Lake (226 Main Ave. E.), notable for its distinctive cobblestone exterior, and has welcomed guests since opening around 1915. The newer Notaras Lodge is a set of cabins built with Washington timber and other touches added by local tradespeople.
A mineralized lake of volcanic origin the lake is the southernmost of a string of lakes in Grand Coulee. It is strongly alkaline and soapy and foams readily when exposed to the winds. Claims that it contains over twenty chemicals and is useful for medicinal purposes are strengthened by the Native American name, which meant witch doctor. A previous name, Sanitarium Lake, was given because a number of these establishments once sprinkled along its shores. Renamed Lake Smokiam in 2012 by the Washington State Committee on Geographic Names.
The community of Soap Lake formerly depended on visitors with ailments which might be cured by the medicinal content of Soap Lake water. It has flourished on increased farming as a result of irrigation from Grand Coulee Dam.