By definition a portable hot tub, also known as a portable
spa, is any hot tub that is not built into the ground. Few people
choose in-ground spas nowadays because they are more costly and
less convenient. The plumbing is fixed in the ground, making maintenance
more of a hassle. Those who choose in-ground hot tub most likely
do so because money is not an issue and they want to have control
over the design.
Just because it’s called portable doesn’t mean it
can be easily moved. A portable hot tub will weigh at least a
few hundred pounds empty. Because of their size and sometimes
awkward shape a large truck must be used for transport. Although
it is possible to move a portable spa, they usually become permanent
These days the terms portable hot tub and portable spa are used
interchangeably. Until a couple decades ago “spa”
referred to a heated tub with jets, usually made from acrylic.
A “hot tub” was a wooden tank, filled with water,
heated and equipped with jets. Eventually acrylic tubs became
much more popular because they are easier to maintain and feature
a contoured design.