Wisconsin Dells, Wisconsin
One-day admission: $35
Wisconsin Dells is known for its water parks, and Noah's Ark is king of 'em all. There are 70 acres of attractions, making this the biggest water park in the U.S. Buy your tickets before you go: $35 is an online-only price that lets park-goers save up to $8. There are also junior, senior, and military discounts.
What's worth the lines: Raja, a new 335-foot tube slide into the mouth of a cobra that includes twists, turns, and a 37-foot plunge.
San Dimas, California
One-day admission: $39
Have a blast splashing your way through 50-acre Raging Waters, one of the biggest water parks on the West Coast. It even boasts an H2Go ride reservation system, which lets visitors pay more to reserve times on popular rides and skip the line. Be sure to buy tickets in advance, as $39 is discounted up to $7 from gate prices. Kids and seniors will also get discounts, and tickets are cheaper on certain Tuesdays.
What's worth the lines: Seven-story Drop Out, one of the nation's tallest vertical slides. You'll hit close to 40 mph during the blisteringly fast four-second drop.
One-day admission: $60
Once you've had enough history lessons in colonial Williamsburg, cool down at Water Country USA, the largest water park in the Mid-Atlantic. Highlights include Surfer's Bay, a massive wave pool, and the nearby Kritter Korral, perfect for little ones who want to splash. Though $60 may seem steep, you can actually snag a season pass for the very same price and splash all summer.
What's worth the lines: The Colossal Curl, which sends rafts of up to four people spinning through a giant funnel and hurtling over a high-walled wave feature.
Federal Heights, Colorado
One-day admission: $42
You'll have tons of choices for fun at Water World, a 64-acre park that has 50 rides ranging from high-speed thrill slides to family-friendly tube rides and play areas. Need a cheaper ticket? Children and seniors pay reduced rates, and there are a variety of other money-saving promotions — for instance, you can save $8 by picking up a coupon at Subway.
What's worth the lines: Lost River of the Pharaohs, which sends large, circular rafts down a twisting white-water slide and into an ancient pyramid where adventure awaits.
One-day admission: $65
Anyone who's underwhelmed with the concrete-jungle feel of most water parks will want to check out Blizzard Beach and Typhoon Lagoon, where the Disney touch is obvious. At Blizzard Beach, you'll splash your way through a melted ski resort; at Typhoon Lagoon, you're a castaway in a tropical paradise ravaged by a storm. Tickets are pricey — this is Disney, after all — but they get you into both parks. Kids get a $6 price break, and tickets are slightly cheaper if you don't go during summer months. Planning on visiting the rest of Disney World, too? Look into Park Hopper Plus tickets.
What's worth the lines: Summit Plummet at Blizzard Beach, which hurls riders down a massive 12-story "ski slope" and into a dark tunnel.
One-day admission: $26.40
Budget-friendly Lost Island is a hit with families who love being able to splash around with the kids for a lower price than they can at many other water parks. For an extra fee, kids can even swim with a mermaid when they're tired of slides, or towel off and enjoy adventure golf or Go-Karts. Discounts are available for kids, seniors, military, and AAA members.
What's worth the lines: Molokini Crater, which sends up to four riders shooting through an enclosed tunnel and through a massive 60-foot funnel, then under a waterfall before splashdown.
Santa Claus, Indiana
One-day admission: $49
Paying for a ticket at Splashin' Safari gets you double the fun, because you can also use it at holiday-themed Holiday World, a traditional theme park with wooden coasters, shows and other favorites. Though anyday tickets are $49 online, look up "pick your price" tickets. If you can go on a non-peak day (for instance, the middle of the week), you can save a tidy sum.
What's worth the lines: Mammoth, the world's longest water coaster, propels six-passenger rafts up and down a 1/3-mile path that can leave riders facing sideways or backwards, or plunge them into darkness.
Powells Point, North Carolina
One-day admission: $40
A brand-new water park in the Outer Banks, H2OBX gives vacationers a thrilling alternative to the Atlantic surf. With a manageable size and a balanced blend of thrill rides, family rides, and kiddie attractions, it's a good pick for all ages. Discounts are available for local residents, military, and those staying in partner vacation rentals. Just want to splash away the evening? Twilight tickets, good after 3 p.m., are only $29.
What's worth the lines: Rogue Wave, a six-story raft ride that sends circular rafts down a large chute and slipping and sliding up and down a massive wave feature.
Pocono Manor, Pennsylvania
One-day admission: $79 and up
If you despise getting all lathered up with sunscreen, Kalahari Poconos is for you. It's home to the country's largest indoor water park, with roughly two dozen slides and water attractions — more than many outdoor competitors. The admittedly steep day-pass price is probably meant to encourage visitors to stay at the attached resort, which allows free admission to the water park for registered guests.
What's worth the lines: Tanzanian Twister, which sends single riders around ... and around ... and around a giant funnel flume at up to 40 mph.
Calverton, New York
One-day admission: $44
City dwellers who want to cool off during a stifling NYC summer can cool off on Long Island at 96-acre Splish Splash. If you're looking for something truly different between rides, be sure to catch the "Cheep Thrills" exotic bird show that puts trained parrots through their paces. Buy online for the $44 price; seniors and kids are just $34. Visitors should also check the park's promotions page for limited-time deals, including coupons available at Dunkin' Donuts.
What's worth the lines: Bootleggers Run, a water coaster that hits up to 30 mph as up to four riders in a toboggan-style raft slide up, down, and around hairpin turns.
One-day admission: $50
Aquatica Orlando, Sea World's first water park, offers a colorful array of attractions with a lush, tropical-themed look. Most rides are named after animals, of course — and the Dolphin Plunge ride even sends riders racing through a clear tube that takes them straight through a pod of dolphins. If you can buy your ticket at least a day in advance online, you'll nab tickets for $50 — $15 cheaper than same-day tickets. Planning on heading to SeaWorld or Busch Gardens Tampa Bay? Combo passes are discounted online, too.
What's worth the lines: Thrilling Ihu's Breakaway Falls, which drops you eight stories after the floor drops out from underneath you.
Pigeon Forge, Tennessee
One-day admission: $50
Spend some time at 35-acre Splash Country and you'll feel like you found your own little mountain hideaway. This sister park to Dollywood even lets you rent 200-square-foot retreats or 65-foot canopies to truly unwind. Visitors planning on spending time at Dollywood will want to look into combo passes for modest savings. Kids and seniors get $5 discounts; there are also a range of limited-time promotions most years.
What's worth the lines: The new five-story TailSpin Racer, which lets riders on rubber mats race each other to the bottom through twists, turns, and drops.
One-day admission: $29
Wings & Waves is smaller and cheaper than a lot of the entries on our list, making it a great place for a fun family afternoon that won't break the bank. This unique indoor water park features plenty of cool aviation details, including attractions that let riders slide out of a roof-mounted Boeing 747. Admission to the water park is only $20 for smaller children and $10 for chaperones who don't want to swim. When you dry off, you can also visit the Evergreen Aviation & Space Museum in the same complex, for a separate admission fee.
What's worth the lines: Mach 1, a traditional enclosed tube slide that one or two riders tackle without rafts.
One-day admission: $44
The 69-acre Six Flags White Water is the Southeast's largest water park and has a little something for everyone, including a huge kids' water playground with an interactive pirate ship and a 700,000-gallon wave pool. Buying tickets online in advance can save you a few bucks on the $44 any-day price; kids also get in at a reduced rate.
What's worth the lines: The multi-lane Wahoo Racer, which sends six riders screaming down a colorful maze of tubes on a head-first, stomach-down race to the finish line.
One-day admission: $35
Wet 'n' Wild proves there's plenty of fun to be had off the Strip in Vegas. Though the 20-acre park isn't as big as some, it packs in more than 25 slides and attractions including family favorites and thrill rides like the tightly coiled Constrictor tube slide. Buy online to get tickets for $35 — they're $5 more at the gate. Kids get a $5 discount on tickets, and this park is a particularly great deal for seniors, who pay only $10 to get in.
What's worth the lines: Zipp Zapp Zoom, a multicolored slide that riders can tackle with an interactive slideboard that lets them become gamers, tapping controllers as they pass under corresponding LEDs.
One-day admission: $40-$46
Indoor Splash Lagoon boasts the largest indoor wave pool in the eastern U.S. and so much more: nine slides, several pools and splash zones, and even a ropes course above it all. Visitors can save by coming in the warmer months and after 4 p.m. There are also plenty of rotating promotions.
What's worth the lines: Hurricane Hole, which shoots riders out of a tube at 40 mph and into a huge funnel, ultimately plunging them into a 6-foot-deep splash pool.
One-day admission: $30
Cheerful, family-friendly Zoombezi Bay near Columbus has just over a dozen slides and attractions, putting it among the smaller water parks on this list, but it also comes with a smaller price tag. And there's another big perk: Your admission includes access to the massive Columbus Zoo and Aquarium right next door, regularly recognized as one of the nation's best zoos. Seniors and kids get a $6 price break, and local Kroger grocery stores often carry discounted tickets for everyone.
What's worth the lines: SoundSurfer: King of the Beats lets riders choose from eight different themes with different lights and sounds to enhance their ride down to a misty splashdown.
One-day admission: $34
Dallas-area residents can take a break from the area's brutal summers at Six Flags Hurricane Harbor, which spreads out on 50 acres and includes two million-gallon pools for frolicking. On certain summer nights, you can even catch a "dive-in movie" on a big screen over the wave pool. Buy tickets online at least three days in advance and you'll save a couple bucks on the online any-day price of $34.
What's worth the lines: The covered tube slides of Black Hole, which keep riders twisting and turning in near-total darkness, save for tiny lights along the way.
Old Forge, New York
One-day admission: $34
Tucked away in the Adirondacks, Enchanted Forest Water Safari boasts 32 heated outdoor water rides as well as some traditional amusement rides like bumper cars, a tilt-o-whirl, a giant arcade, and more. Kids' tickets are $4 off, and the $34 price reflects a small discount over gate prices. Park-goers who arrive after 3 p.m. get in the next day for free.
What's worth the lines: Up to five riders can kick back on the Amazon, a 1,100-foot family tube ride that twists and turns through the trees.