I leaned back on my floatie and watched as my eldest daughter practiced her underwater somersaults. Nearby, my husband coached our youngest into her first dog paddle.

The pool, surrounded by flowers and potted fruit trees, was the perfect place for our family to be during the early evening heat — but it wouldn't be ours for much longer. We were in a private pool in a stranger's St. Paul backyard, and had only a few minutes left on our reservation.

The pool, listed as the "Montrose Moderne," is one of about a dozen in the Twin Cities for rent by the hour through Swimply, an app that aims to be the Airbnb of pools. Homeowners with pools list the dates and times the pools are available, and would-be swimmers can book them by the hour. (Local rates range from $40 to $100.)

It's part of a recent burst in peer-to-peer sharing apps, which let you rent someone's car (Turo and Getaround), camper (Outdoorsy) or even a fenced yard to play fetch in with your dog (Sniffspot).

Swimply started in 2018, when it launched a test version with just four pools in New Jersey. It took off during the pandemic, when people sought out private spaces to have fun, and continues to expand.

While most of Swimply's more than 5,000 pool listings are in California and other warm-weather locations, its founders say there are lots of eager swimmers in the Midwest, where backyard pools are less common — and more coveted during a heat wave.

"The best opportunities for us are not in Arizona, or Florida, it's actually places like Minneapolis, where there are fewer pools," said Swimply co-founder Asher Weinberger. "The supply-demand ratio is so skewed, and there's so little time to enjoy pools because of the seasons. People really are motivated."

Minnesotans, it seems, are not only motivated to dive into other people's pools, but to rent out pools, if they have them.

"You have this pool you hardly ever use, and it costs money all year but you're only using it for a short period of time," said Weinberger. "It's like, 'How do I recoup that investment?' "

He made more than $20,000 renting out his own New York pool through the app last year. The company collects a percentage from both hosts and swimmers, and provides benefits like insurance coverage.

Rental regulars

While some local Swimply hosts said they rent out their pools to cover the costs of opening, closing and maintaining them, others find it rewarding in a different way.

St. Paul couple Ed Piechowski and Sean Ryan, whose in-ground, 40-foot pool my family rented, said it makes them feel good that other people are enjoying their space when it would otherwise sit empty.

"It's been really wonderful for us," said Piechowski. "Our pool lies dormant 350 days out of the year. And so for us, sharing it with everyone who uses it all the time, it's a gift. We really believe it's a gift."

Aside from the 40-minute after-work swim they take every day, they don't use the pool much. They had long joked about creating a Montrose Swim Club, so friends could sign up to use the pool.

Now, they have Swimply regulars — some of whom prefer just to lounge by the pool in a chaise and read a book for the entire reservation period.

Ryan and Piechowski began hosting swimmers in June 2020. Back then, many people were still wary of catching COVID-19 from surfaces, but the Centers for Disease Control had said that chlorinated water didn't pose a risk.

They admit that renting out their pool felt a bit strange at first.

"It was really weird during the pandemic to have people come into your space, or even your yard," said Piechowski. "But people loved it. We loved it."

We loved it, too. But I was a little apprehensive about letting ourselves in to a stranger's backyard and jumping in their pool. And yet, our Swimply experience felt like a mini-staycation.

In fact, I got so relaxed that it was a little jarring when a neighbor appeared on the deck next door. But she gave a friendly nod, and our girls were oddly well behaved, intent on practicing their swimming instead of yelling and splashing each other. And because the pool had a pool house, there was an accessible, comfortable place for us to change in and out of our suits.

If you stay for more than an hour, the price to rent the average pool is a little steep compared with area public aquatic centers, which charge about $10 a person for a daylong pass. But then you have the luxury of having a pool all to yourself.

Ryan and Piechowski said a few renters have shown up with more people than they booked for. (There's a 15-guest limit, and extra fees for more than five people.) And, at times, enthusiastic kids can be too noisy for the neighbors. (The couple encourage louder guests to come before 5 p.m.) But overall, the experience has been overwhelmingly positive — even though they've made only enough to offset the pool's maintenance costs.

"As they say, 'A pool is a hole that you throw water into, then plenty of money,' " Ryan said. "We're just happy to share the space with others and give folks an option besides the lake or municipal pool."

'Big blue splotches'

In 2018, when Swimply was just starting, Weinberger and co-founder Bunim Laskin used Google Earth to find potential Swimply pools in the New Jersey area.

"We looked for big blue splotches from the sky. And then we went knocking on doors," said Weinberger. "We got kicked out of 76 of them. But we did get four pools to sign up."

Now the app includes pools in more than 125 U.S. cities and several locations in Canada and Australia.

As Swimply's platform grows, the company continues to update and improve its app. Still, I found it easier to sign up and set up a profile using the company's website platform (Swimply.com) because I had trouble using the app on my phone.

And while I was able to secure a reservation at Montrose Moderne fairly quickly, other Twin Cities area pool hosts took several days to get back to me, only to tell me they were already booked.

Once we got our toes in the water, though, it was easy to see why Swimply has caught on. With the pool to ourselves, I was able to relax and watch as the girls swam, instead of squinting to keep track of which kid was mine in a busy public pool. The hardest part was persuading the kids that yes, we really did need to leave.

Erica Pearson • @ericalpearson