Before installing a hot tub, the first consideration is proper placement and adequate flooring. Typically, hot tubs are situated outdoors either above ground on a deck, patio, or concrete slab, or built into the ground. Hot tub materials range from concrete, fiberglass, plastic, acrylic and wood lined with a composite material. Many people, however, choose to install an indoor unit for greater privacy, convenience, or personal preferences. An empty hot tub can weigh as much as 800 pounds. Adding water can increase the weight up to 2,000 pounds. Adding four adults can increase the weight by another 600 pounds or more. Because of this hefty weight strain on a home or deck structure, it is imperative to ensure the strength of the foundation below. When in doubt, a structural engineer should be consulted to provide a stability assessment.

When installing a hot tub indoors, the chosen room should be well ventilated. Proper, level flooring is essential to support the weight and withstand substantial water exposure. Carpeting should be eliminated from the list of options, as wet carpet breeds mold, mildew, and bacteria and can lead to serious water damage of the sub-flooring. Ceramic tiles are perhaps the most practical flooring solution. They are designed to withstand constant moisture and are very easy to clean. A floor drain can easily be installed in tile flooring. Tile can be slippery when wet, however, and many people choose to lay a perforated, interlocking grid pallet made of sturdy, non-slip rubber or vinyl underneath and around the hot tub perimeter. This is also a smart choice on top of a concrete floor.

Other flooring choices for indoors include sheet vinyl flooring and laminate materials. Sheet vinyl comes in several designs, colors and textures; many styles simulate wood grain, ceramic tile, river rock, marble, flagstone, and brick, and the same is true for many of the laminates. Durable sheet vinyl is easy to install, can be cut to size and washes well. As with ceramic tile, sheet vinyl is also a safe floor-protecting choice when using hot tub chemicals and can be bleached if necessary to kill any mold growth. If using sheet vinyl, baseboard trim should be added to secure it to the sub-flooring and then caulked well.

While real wood flooring is not a wise choice indoors, the newer laminates look just like wood and are now available in waterproof materials. Previous models used fiberboard centers that would swell, buckle, or separate with heavy water exposure. Some newer versions use a waterproof PVC center that is honeycombed to provide some spring or cushion to the floor. This is installed using a layer of foam film between the sub-floor and the laminate to provide a moisture and sound barrier.

When no deck or patio exists, outdoor installation can be easily accomplished on clear, level ground. Poured concrete is a durable, long-lasting base that should be reinforced and poured at least 4 inches thick. Prefabricated spa pads made of interlocking, rigid, waterproof material are an affordable, maintenance-free alternative to concrete and can be easily moved. Gravel, crushed rock, or concrete pavers also make an excellent base. They serve to help protect hot tub filters by catching dirt and debris before entering the unit. Perimeters of flagstone, wood decking, or brick also help keep the surrounding area clean while adding a nice finishing touch to the setting.