Commercial spas have increased in popularity over the years, primarily due to three significant changes. First, because they fit into certain applications where concrete or tiled spas do not meet the customer’s criteria or location requirements; second, residential spas are not deemed acceptable, primarily due to the different design properties of the various engineering firms responsible for specifying spas; and third, updated municipal, provincial, and federal health and building codes—along with new industry standards—have contributed to the shift toward specially designed, constructed, and engineered units.