Spillover spas and hot tubs next to the pool

A spillover spa is a small, deep, heated body of water set at the edge of the pool, usually a little higher than the pool surface. When the system runs in pool mode, water is pumped into the spa and pours over a lip or a notch in the spa wall back into the pool. That spill is the look most people want. When you switch to spa mode, valves close off the pool, and the pump and heater work only on the spa water so it gets hot fast.

Pentair's IntelliCenter control describes the spillway function in plain terms: in a pool and spa combination, pool water is diverted to the spa and spilled back into the pool. The same controller can schedule the pump and heater to warm the spa before you get home.

A spillover spa is not the same as a hot tub on the patio. It is built into the ground with the pool, plumbed to the same equipment pad, and finished with the same coping and deck. It looks like one project because it is one.

Both have a place. Here is how we talk it through with homeowners.

If you picture sitting in hot water on a January night in Chardon with snow on the deck, a standalone hot tub is the honest answer. It is built for that, and it does not depend on keeping the pool's plumbing open through a Northeast Ohio winter. If you want the spa as part of the pool, for cool May evenings, September nights and the view of water falling into the pool, the spillover spa is the better fit.

Some families do both: a spillover spa for the season and a pad with power roughed in for a hot tub later. That choice is easier to make before the deck is poured.

We build with Liberty Composites fiberglass, and Liberty makes two spa shapes, each available as a spillover.

• Blessing Spillover: 9 ft 8 in by 10 ft 6 in, 3 ft 4 in deep, about 550 gallons.
• Refinement Spillover: 8 ft 6 in by 9 ft 8 in, 3 ft 4 in deep, about 600 gallons.

Compare that with a pool. Liberty lists the Hero 12x26 at about 7,000 gallons. The spa holds less than a tenth of that, which is why a heater can bring it up to soaking temperature in a fraction of the time it takes to warm the pool.

The spa shell sits on its own base beside the pool and is backfilled and plumbed at the same time. Its top usually sits above the pool's water line so the spill has somewhere to fall. We set that height in the 3D design so you can see how the spa lines up with the pool, the deck and the view from the house.

Yes. With an ICF concrete pool, the spa can be formed as part of the same insulated structure, in almost any shape, including a spa that sits right on a pool wall with a wide sheet of water pouring over. The insulated walls help the spa hold heat, which matters on the cool evenings we get here in May and late September.

Latham, which makes the vinyl liner products we install, offers spa and spillover spa models that can be added to both fiberglass and vinyl liner pools. We will walk you through the combinations for your yard at the design stage.

The spa uses the pool's heater, so the heater choice covers both. For a spa, speed matters. People want it hot soon after dinner, not tomorrow, and most of our clients here pick a gas heater, natural gas or propane, because it brings a small body of water up to temperature quickly.

A heat pump is efficient for holding a pool at temperature through the summer, but it slows down as the air cools, and the spa is often most wanted on the coolest nights. Some owners pair a heat pump for the pool with gas for spa use. It is a real conversation to have with us, and it depends on whether you have natural gas at the house or would need propane.

Keep the water at or below 104 degrees. The Consumer Product Safety Commission says hot tub water should never exceed 104 degrees and treats 100 degrees as safe for a healthy adult. It advises pregnant women to stay at 100 or below and warns against drinking alcohol in the spa. We set the controls to respect that.

Cover the spa when it is not in use. The Department of Energy says evaporation is by far the biggest source of heat loss from a pool, and the same physics apply to a spa. A fitted cover keeps the heat you paid for.

Pools and spas in Ohio are held to barrier rules based on the International Swimming Pool and Spa Code (ISPSC). North Olmsted's building division, for example, tells residents that a barrier complying with ISPSC Section 305 is required around the entire pool.

The ISPSC has a specific rule for spas and hot tubs. The International Code Council explains that where a spa or hot tub has a lockable safety cover complying with ASTM F1346, the area does not have to meet the barrier sections 305.2 through 305.7. That exemption matters for a standalone hot tub on a deck. For a spillover spa, the pool beside it still needs its barrier, so the fence is usually there anyway.

Towns can and do add their own rules. We handle the permits on every project and check with your building department, whether that is Hudson, Stow or Canton, before we finalize the design.

• Where the spa sits. Most people want it closest to the house for short, cold walks in October. Think about the view from the spa, too.
• How it spills. A single notch, a wide spillway across the whole wall, or a sheer descent over a raised wall. Each changes the sound.
• Controls. Automation lets you heat the spa from your phone on the drive home. With a spa, most of our clients find it worth adding.
• Lighting. A spa light on the same color scheme as the pool's Pentair LED lights ties the two together at night.
• Steps and seating. Check the bench layout against your family. A spa with one long bench and a lounger suits two people. A group of six wants bench seating all the way around.
• Future hot tub pad. If you might add a standalone tub, plan the pad and power now.

A spillover spa is an upgrade on top of the pool package, and it adds to the cost and the build schedule. We price it in the same quote so you see the whole number at once, and our lending partners can finance it with the pool.

This is the reason most of our clients add one. The swim season here runs roughly Memorial Day to Labor Day. A heater and a cover stretch the pool a few weeks each way. A spa does more than that: a small volume of water, heated fast and covered, is comfortable on nights when nobody would get in the pool.

At closing time, the spa is winterized with the pool. Its lines are blown out and plugged, and the water level is managed with the rest of the system. If you want to keep soaking into late fall, we can talk through a later closing date, but a spillover spa shares the pool's plumbing, and once hard freezes arrive, protecting that plumbing comes first.