Typical spas are designed around dimensional lumber and are usually very linear in shape. Some deviations do occur in certain models but only on one or two sides. Spas with very linear shell shapes require very linear frames that are easily constructed with dimensionally-squared lumber, like standard two-by-four or two-by-two lumber. As a consequence, traditional spas are very squared or rectangular. In a square or rectangular spa, rounded seating space is sacrificed as it is fit as best as possible into squared corners.
Typical linear spas are very plain looking, especially when the cover is on and they are not in use. Linear spas are not architecturally pleasing and are usually not a focal point for the customers' landscape architecture. Accordingly, many spa owners hide their spas with landscaping or put them inside structures such as gazebos.
The typical spa is designed with primarily with only hydrotherapy in mind. Some spa designs do provide an additional water feature, which usually entails a plumbing device to pump out water into the main body of water of the spa. These waterfalls are for mostly for visual effect, typically lit with lights or other optic features, and achieve a very artificial sound. Other spas also provide sound systems such as stereos, but these systems are also unnatural and can detract from the therapeutic aspects of the spa.
Another limitation in most spa designs is ingress and egress. Spas rarely have internal steps because they sacrifice too much seating area. Coupled with the awkward seat configurations found in most linear spas, ingress and egress for a user of a typical spa is difficult. Yet another limitation in typical spa designs is the placement and functionality of the filter bucket. Most filter buckets occupy a “dead area,” i.e., an area of the spa that cannot be utilized for hydrotherapy or other uses. Because of their single function of continuously receiving large amounts of water for filtering and pumping, filter buckets are not conceived of as an aesthetic element of the overall spa design.