The first and most critical decision in SPA design is the shape of your SPA. This choice directly impacts not only visual aesthetics but also how the SPA will be used and how many people can comfortably enjoy it simultaneously. Round or oval shapes are generally among the most popular choices, offering a natural seating arrangement for conversation and socializing. Oval and elliptical shapes can add a bit more visual appeal compared to purely round forms. For those seeking a more modern and bold look, angular shapes like squares, rectangles, or triangles can also be chosen. It's even possible to add a personal touch with more unusual geometric forms such as hexagons or diamonds. For lovers of curved lines, shapes like horseshoe or semi-circle can create a unique atmosphere, reminiscent of classic Roman pools. During the design process, you can have a detailed discussion with your pool builder to bring your dream shape to life. Choosing a shape that harmonizes with the overall structure of your existing or planned pool will provide a cohesive aesthetic. For instance, you can make a square SPA with sharp corners more inviting with soft transitions, or add curved edges to a triangular SPA for a modern touch. Even a simple circular shape can be made much more unique and contemporary with minor modifications to its edges (such as straight or inverted edges). If you're considering a rectangular SPA, designing it as an integrated part of the pool will provide a modern and fluid appearance. If your pool design has a more natural or rustic theme, you can create a harmonious and relaxed atmosphere using free-form organic shapes. This flexibility allows you to shape your SPA entirely according to your personal tastes.

An inground SPA can be built as a separate structure from the pool, or it can be an integrated part of a cohesive pool design. Some homeowners might prefer to position the SPA away from the pool, closer to the house, due to backyard layout or home location factors. However, the most common and aesthetically pleasing method is to make the SPA a part of the overall pool structure. There are two main ways to incorporate a SPA into an existing setup. The simplest and most cost-effective approach is to include the SPA within the pool itself. In this scenario, the SPA is structured as a largely separated section within the pool's interior. For frequent pool users, the SPA serves as an excellent spot for a break and relaxation. The second method is to build the SPA outside the pool's perimeter, but sharing a portion of the pool wall and connecting to the pool at that point. Whichever path you choose, you'll need to define a common dam element that separates the water from the pool. This dam wall not only provides a ledge to hold onto in the SPA but also helps maintain the hot water within the SPA. You can aesthetically shape this functional dam wall as an integral part of the SPA design. Even when a low-profile SPA is preferred, it's possible to use the dam wall as a clever style accent. A chic tile pattern along the waterline or constructing the structure itself with glass blocks at the top can create a visual water art. However, with such choices, it's important to consider various climatic conditions and durability.