Michael Phelps Shares His Favorite (Too Sweet!) Olympic Memory — and What He'll Miss the Most

Michael Phelps has won 28 Olympic medals, but all those times on the winner’s podium aren’t his favorite memories from the Olympics.

The former swimmer — who is the most decorated Olympian of all time — opened up to PEOPLE about the highlights of his storied career while chatting about partnering with Colgate as the ambassador for its Save Water initiative for the fifth annual Imagine a Day Without Water.

“Being able to have Booms and Nicole and my family in the stands for my last Olympics was something super special,” Phelps tells PEOPLE of his oldest son Boomer, 3, and wife Nicole Phelps, 34, joining him for the 2016 Olympics in Rio. He continues, “Looking back on my career, I did everything I ever wanted to do in the pool. So it was a good ride, it was a fun ride. I think it’s even more enjoyable now to turn the page to what we’re doing next. That’s something that’s even cooler.”

Still, the retired Phelps will miss some things as the athletes hit the world stage next summer in Tokyo — marking the first Summer Olympics that Phelps hasn’t competed in since 2000.

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“Being able to represent your country is something that — it’s one of the things I’ll probably miss the most,” he says. “Not being able to wear the stars or stripes anymore on international ground and competing.”

He also has some wise wisdom for athletes competing on that level for the first time: “Don’t worry about the lights.”

“Because that’s the biggest thing that people get freaked out about,” he says of the increased attention. “The Olympics is another swim meet. The lanes are in the same exact width, the pool is the same exact depth, it’s nothing different. Same exact temperature people swim in their whole entire life.”

In his role as a Save Water ambassador, Phelps tells PEOPLE he’s learned a lot — and he’s implementing his new water-saving techniques around the house with his three kids, including sons Boomer, Beckett Richard, 20 months, and Maverick Nicolas Phelps, 1 month.

“Water is something that will always be a part of my life, it’s been a massive part of my life from the beginning of it,” he says. “So I think for me, now having a family of five where, for Nicole and I, this is something we’ve done all of our life — turn the water off when we’re brushing, make sure we’re saving as much as we can because we know how important of a resource it is.”

He continues, “Can you imagine a day — you can’t brush your teeth, you can’t rinse your brush, you can’t take a shower, you can’t flush the toilet, you can’t do the dishes? You can’t even have a cup of coffee. All these things that include water, and at some point there could be no more water. So it’s just for me, something that I’m encouraging and begging everybody to just get on board.”

The 2019 Imagine a Day Without Water — last Thursday — helps to raise awareness of the importance of preserving the planet’s most precious resource.

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“Don’t ever have water just constantly running,” Phelps advises. “It’s just something that I want to be able to get out and be able to save as many gallons as we possibly can for my kids, and future kids to come so they can have everything that we’ve had. We’ve been so fortunate to be able to turn on the faucet and have clean water. Let’s keep it going for everybody else.”