Pool Hot Tub Design Visualizer
and Hot Tub
Configure every detail of your pool and spa combination: pool type, spa configuration, spa size, jet package, pool shape, interior finish, water features, coping, deck, landscaping, lighting, heating, and automation. The live preview updates with every choice.
Design Your Pool and Hot Tub, One Decision at a Time
A pool and hot tub combination is the most popular residential water feature package in the United States. The hot tub extends the swimming pool’s useful season into cooler months, adds a relaxation and hydrotherapy element that a pool alone cannot provide, and creates the resort atmosphere that most homeowners picture when they first imagine their backyard transformation. The design decisions for a pool with a built-in spa are more complex than either a pool or a hot tub alone, because the two elements must work together structurally, hydraulically, aesthetically, and functionally.
This tool walks through all 22 design decisions for a pool and hot tub combination, one per step. Work through them and you will have a complete specification covering every decision your pool contractor needs to design and price the project accurately.
Live Pool and Hot Tub Preview
Afternoon ViewPool Hot Tub Designs: Spa Configuration, Spillover, and Built-In Spa Options
The most important single decision in a pool and hot tub project is not the pool shape or the interior finish. It is how the spa connects to the pool. The spa configuration determines the visual relationship between the two water bodies, the hydraulics of how water moves between them, the structural requirements, and how the two elements feel to use independently and together. Getting this decision right before design begins saves significant cost and disappointment at the end of the project.
Attached Spillover Spa: The Most Popular Pool and Hot Tub Configuration
An attached spillover spa is raised 12 to 24 inches above the pool water level and built adjacent to the pool so that water continuously spills over the shared bond beam wall when the spa is running. The cascading water creates a visual and audio waterfall effect, gently heats the adjacent pool water, and provides a constantly visible resort element even when no one is using the spa. The spillover spa is the dominant residential pool and spa configuration in the United States because it adds the most visual drama for the cost, it physically integrates the spa and pool into one cohesive design, and the spillover waterfall is arguably the most attractive water feature available in residential pool design. The structural requirement is a bond beam wall between the spa and pool that is engineered to handle the lateral load of the raised water body. In gunite construction, this wall is formed in the same concrete pour as the rest of the pool shell.
💦Shop Spa Hydrotherapy Jets on AmazonReplacement and upgrade jets for built-in pool spa and hot tub systems→Raised Equal-Level Spa and Negative-Edge Spa
A raised equal-level spa sits at the same elevation as the pool water surface, with a shared bond beam wall at water level. Water overflows continuously between the two bodies at a controlled rate, creating a gentle visual connection without the dramatic height differential of a spillover configuration. This design is popular in contemporary and minimalist pool aesthetics because the two water bodies read as one continuous surface with a subtle dividing line rather than two distinct elements. A negative-edge spa, also called a perimeter-overflow spa, has the spa water level set at the top of all four walls so that water flows evenly off every edge of the spa into a surrounding catch basin or directly into the pool. The effect is dramatic, particularly when the spa is illuminated at night and the water cascades on all sides, but it requires a carefully engineered overflow channel and return system.
Spool: The Small-Pool-and-Spa Combination
A spool is a combined small pool and spa, typically 8 to 14 feet long, that is designed to function as both a spa with full hydrotherapy jets and a small pool for wading, lounging, and cooling off. Because the volume is small, a spool heats quickly (often within an hour with a gas heater), making it practical and cost-effective for year-round use in most climates. Spools have become popular as the primary water feature for smaller lots and urban backyards where a full-size pool with an attached spa would not fit. The cost of a spool runs approximately $20,000 to $60,000 depending on construction type, finish specification, and jet package, which is significantly lower than a full pool and spa combination.
Pool and Spa Heating Systems, Jet Therapy, and Year-Round Operation
Shared vs Dedicated Spa Heating Circuits
The most common pool and spa thermal configuration is a shared filtration system with a dedicated spa heating circuit. In this setup, the pool and spa share the same filter, salt chlorinator, and main circulation pump. When the spa is used, a separate valve configuration diverts the flow through a dedicated heater that raises the spa water to the desired temperature, typically 100 to 104 degrees Fahrenheit, without affecting the main pool. The pool runs at its own ambient temperature. This configuration is the most cost-effective to build and the most flexible to operate: the pool stays at a comfortable swim temperature during the day and the spa heats to a hot soak temperature for evening use.
A dedicated spa heater provides the fastest possible spa heat-up time, typically 30 to 60 minutes from ambient temperature to 102 degrees Fahrenheit using a gas heater on a standard 4 to 6 person spa. A heat pump is more energy-efficient but takes 2 to 4 hours to reach the same temperature from cold. For homeowners who use the spa spontaneously rather than on a schedule, a gas heater or a gas heater paired with a heat pump for maintenance heating is the practical choice. For homeowners who use the spa on a regular schedule and keep it preheated, a heat pump with a thermal spa cover is the lowest operating cost option.
♨️Shop Spa Covers on AmazonInsulated thermal spa covers and cover lifters for pool hot tub systems→Spa Jet Systems: Booster Pump, Jet Count, and Hydrotherapy Zones
Spa jets in a built-in gunite spa are fed by a dedicated booster pump separate from the main pool circulation pump. The booster pump creates the pressure differential that drives water through the jet nozzles at the velocity needed for massage therapy. The number of jets and their positions determine the coverage and the character of the hydrotherapy experience. A basic jet package with 10 to 15 jets provides a gentle overall massage suitable for relaxation. A standard 20 to 30 jet package provides good coverage of back, seat, and footwell positions. A premium multi-zone package specifically places jets to target the lumbar back, neck and shoulders, calves, and feet as separate controllable zones. A full hydrotherapy system with programmable zone controls is the most complete option and approaches the jet configuration of a high-end standalone hot tub. The booster pump should be sized to the jet count: too small a pump for the number of jets open simultaneously produces weak, unsatisfying jet pressure; too large a pump for a small spa produces uncomfortably forceful jets.
Spa Temperature and Year-Round Use
A spa maintained at 100 to 104 degrees Fahrenheit is comfortable for adults for sessions of 15 to 30 minutes. USA Swimming and most medical references cite 104 degrees Fahrenheit as the safe upper limit for spa water temperature. Children under 5 should not use spa water above 95 degrees Fahrenheit. Pregnant women should consult a physician before using spa water above 100 degrees Fahrenheit. The energy cost of maintaining a spa at temperature year-round is manageable with a quality insulating spa cover. A well-fitted foam-core thermal cover with an R-value of R-12 or higher reduces heat loss by 60 to 75 percent and cuts monthly spa heating costs from $50 to $100 down to $15 to $30 in most climates. Automatic safety covers that motor open and close at the touch of a button are used more consistently than manual covers and therefore save more energy in practice.
Pool Hot Tub Cost, Safety Requirements, and Water Chemistry
Pool and Hot Tub Combination Cost Guide
The cost of a pool with a built-in spa includes all of the standard pool costs plus the spa shell, spa plumbing and jets, the booster pump, the spa heater, and the shared automation system. For a standard medium-size gunite pool with an attached spillover spa, the total project cost including pool, spa, coping, basic deck, equipment, and safety fence runs $75,000 to $130,000. A freestanding portable hot tub added near an existing pool or new pool runs $4,000 to $16,000 for a quality unit and does not require the structural engineering and additional plumbing of a built-in spa.
Pool and Spa Safety Requirements
Both the pool and the spa in a combination system are subject to the same safety barrier requirements under the International Residential Code (IRC) Section R326 and applicable state codes. A barrier at least 48 inches high surrounds the entire pool and spa enclosure, with self-closing, self-latching gates opening away from the water. The gate latch is positioned at the top of the gate or on the pool-side face so a child cannot reach through from outside to operate it. Anti-entrapment drain covers on all main drains in both the pool and the spa must comply with the Virginia Graeme Baker Pool and Spa Safety Act (VGBA). The spa drain in particular must have a VGBA-compliant anti-entrapment cover because spa drains produce stronger suction relative to volume than pool drains. Pool bonding under NEC Article 680 connects all metal components in and around both the pool and the spa. The spa jets, jet pump housing, light fixtures, and all metal handrails must be included in the bonding system. GFCI protection is required for all electrical outlets within 20 feet of a pool or spa and for all 240-volt equipment including the spa heater and booster pump.
⚙️Shop Pool Safety Fencing on AmazonCode-compliant 48-inch pool safety fencing with self-latching gates→Salt Water Spa and Pool Chemistry
Salt chlorinator systems generate chlorine from dissolved sodium chloride at a consistently low level that suits both the pool and the spa. Salt water is softer on skin and eyes than traditionally chlorinated water, which makes it particularly comfortable for a spa where users typically soak longer and in hotter water than in a pool. The elevated temperature of a spa accelerates chemical demand: chlorine is consumed faster in 102-degree water than in 80-degree pool water, pH rises faster, and total dissolved solids (TDS) accumulate faster. A salt system with a separate cell for the spa, or a combined cell sized for the total system volume, provides consistent automatic chlorination for both the pool and the spa. Bromine is an alternative sanitizer for spas that is more stable than chlorine at high temperatures, which makes it a popular choice specifically for the spa side of a combination system. The pool can run on a salt chlorinator while the spa runs on a separate bromine feeder. Cyanuric acid stabilizer is used to protect chlorine in the outdoor pool from UV sunlight degradation but should not be used in the spa. The pH in the spa should be maintained at 7.2 to 7.6, the same range as the pool. Alkalinity should be maintained at 80 to 120 ppm in both bodies. TDS should be monitored in the spa since the high temperature and frequent refilling with chemicals concentrates dissolved solids faster than in the pool volume.
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