You’re standing in the middle of your backyard with a measuring tape. It’s hot. The kids are already arguing about who gets the big flamingo floatie, and you’re staring at a patch of grass that’s about to be sacrificed for the sake of summer sanity. You’ve seen the boxes at Walmart or scrolled past them on Amazon—the 18 ft Coleman pool. It looks massive in the photos. It looks like a resort. But then you start thinking about the leveling, the gallons of water, and that one neighbor whose pool turned into a giant swamp by July.
Is it actually worth it?
I’ve spent enough time around these "Power Steel" frames to know they aren't just "set it and forget it" projects. If you go into this thinking you’ll just roll out the liner and be swimming in an hour, you’re in for a very long, very sweaty Saturday. But if you get the prep right, an 18-foot round pool is arguably the "sweet spot" of the above-ground world. It’s big enough for adults to actually float without hitting their heads on the ladder, yet it doesn’t require a second mortgage to maintain.
The Reality of the 18-Foot Footprint
Eighteen feet sounds manageable until you realize we’re talking about a diameter that needs a "buffer zone." You aren't just placing an 18-foot circle on the ground. Most local codes and common sense dictate you need at least a few feet of clearance around the perimeter. If you have a small suburban lot, this thing will dominate your view. It becomes the focal point of your entire outdoor life.
One thing people constantly underestimate is the weight. We are talking about roughly 6,000 to 7,000 gallons of water. That is a staggering amount of pressure. If your ground is even two inches out of level, that water is going to push against one side of the Coleman Power Steel frame with terrifying force. I’ve seen liners buckle and legs sink because someone thought "close enough" was good enough for the leveling process. It isn't. You need a transit level or a long 2x4 with a level on top to ensure that dirt is flat. Not "smooth." Flat.
Most of these 18-foot models, like the popular Swim Vista Series with the built-in windows, use a corrosion-resistant steel frame. It’s sturdy. The "Seal & Lock" system Coleman uses is basically a way to make sure the pipes don't slide apart under pressure. It works well, but honestly, the plastic pins can be a pain if you aren't lining them up perfectly.
The Pump Problem Nobody Mentions
Let’s be real for a second. The pump that comes in the box with the 18 ft Coleman pool is usually... okay. Just okay. It’s often a cartridge filter pump that struggles to move the volume of water required for a pool this size.
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If you have four kids and their friends jumping in and out all day, bringing in grass, sweat, and sunscreen, that little 1,500-gallon-per-hour (GPH) pump is going to be screaming for help. Most serious owners end up upgrading to a sand filter pump within the first year. A sand filter, like the ones from Intex or Bestway (who actually manufactures Coleman pools), is a game changer. It filters better, requires less maintenance, and actually has the "oomph" to vacuum the bottom of the pool.
If you stick with the stock cartridge pump, prepare to wash that filter out every single day. If you don't? Hello, green water.
Why the "Vista" Windows are Polarizing
Coleman’s Swim Vista Series adds those reinforced portholes into the side of the 18-foot liner. Kids love them. It’s undeniably cool to see someone swimming underwater from the outside. However, from a long-term maintenance perspective, every hole in a liner is a potential fail point. While the Tritech material—that three-ply reinforced PVC—is tough, the seals around those windows are where you need to keep a close eye. If you’re a "buy it for ten years" type of person, you might prefer the solid wall versions. If you want the "coolest house on the block" factor for the next three to five summers, the windows are a hit.
Setup: The "Two-Day" Rule
The box says "easy setup." That’s a bit of marketing optimism.
Day one should be entirely dedicated to ground prep. Clear the sod. Level the dirt. Lay down a tarp or, better yet, Gorilla Pad or foam insulation boards. If you put this pool directly on top of grass, the grass will die, rot, and smell like a swamp within two weeks. Plus, nutgrass can actually grow right through a vinyl liner. It’s a real thing. It’s heartbreaking.
Day two is the assembly. You need at least two people. Trying to click those 18-foot top rails together alone is a recipe for a pulled muscle and a lot of swearing. Once the frame is up, the "wrinkle dance" begins. You start filling with an inch of water and get on your hands and knees to push the wrinkles out from the center to the edges. If you don't do this now, those wrinkles become permanent "dirt traps" that you’ll be scrubbing for the rest of the season.
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Managing the Chemistry
Water chemistry in an 18-foot pool is more forgiving than a small 10-foot "easy set" ring pool, but it still requires a rhythm. Because you have roughly 6,300 gallons, your chemical swings won't happen quite as fast, which is a good thing.
You’ll need:
- A reliable test kit (the drops are better than the strips, honestly).
- Liquid chlorine or a saltwater generator.
- Cyanuric acid (stabilizer) to keep the sun from eating your chlorine.
- A skimmer net that you actually use.
A lot of people think they can just throw a few 3-inch chlorine tabs in a floater and call it a day. That’s how you end up with high stabilizer levels that eventually "lock" your chlorine and make it useless. You’ve got to test the pH. If the pH is off, the chlorine can’t do its job, and you’re basically swimming in a giant petri dish.
Cost Comparison: Coleman vs. The World
Why choose the 18 ft Coleman pool over an Intex or a permanent above-ground pool?
Price is the obvious driver. You can often find the Coleman 18' x 48" or 18' x 52" sets for significantly less than a permanent steel-walled pool, which can run you $3,000 to $5,000 before installation. The Coleman gives you that "real pool" feel for a fraction of the cost. It’s the perfect "test run" pool. If you find out after two years that you hate the maintenance, you’re only out a few hundred bucks rather than a massive investment.
But remember, the "hidden" costs add up:
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- The water bill to fill 6,000+ gallons.
- The electricity for the pump.
- The inevitable upgrade to a better ladder (the ones in the box are famously wobbly).
- Chemicals and cleaning tools.
Common Misconceptions and Troubleshooting
I hear it all the time: "The pool is leaning!"
If your 18-foot Coleman is leaning, it’s not the pool’s fault. It’s the ground. There is no "fixing" a leaning pool once it's full. You have to drain it, level the ground, and start over. It sucks. It’s a waste of water. But it’s the only safe way.
Another one: "The liner is leaking at the seam."
Sometimes, it’s just condensation. Because the water is colder than the humid air, the outside of the pool can "sweat," making it look like a leak. Check the ground. If it’s a localized puddle that never dries, then you’ve got a leak. Luckily, these PVC liners are incredibly easy to patch, even underwater, with a simple vinyl repair kit.
Longevity: How Long Does it Actually Last?
If you leave an 18-foot Coleman pool up year-round in a climate that freezes, you’re taking a gamble. The PVC becomes brittle in extreme cold. Many people in northern states drain them, dry them completely (this is the hard part), and store them in a garage or basement.
If you live in a milder climate and keep the chemicals balanced, you can easily get 3 to 5 seasons out of one. Some people stretch them to 7 or 8 by replacing the pump and being meticulous with the liner. But realistically, these are "temporary" structures. They aren't meant to be heirlooms. They are meant to get your kids through middle school without them complaining that they’re bored.
Actionable Steps for Success
If you’re ready to pull the trigger on an 18 ft Coleman pool, follow this sequence to avoid the common pitfalls:
- Map the sun: Don’t just put the pool where it looks good. Put it where it gets the most sun to keep the water naturally warm, but stay away from overhanging trees unless you want to spend your life cleaning out leaves.
- Call your insurance: It sounds boring, but check if an above-ground pool affects your homeowner's policy. Some require a fence or a locking ladder.
- Buy a real vacuum: The "venturi" vacuums that hook up to a garden hose are useless for an 18-foot pool. Get a vacuum that attaches to your pump's suction line.
- Level like a pro: Dig down to the lowest point; never build up with loose dirt. Loose dirt will compress under the weight of the water, and your pool will tilt.
- Shock it early: Don't wait for the water to look cloudy to add shock. Start a maintenance schedule the moment the pool is full.
The 18-foot Coleman is a beast of a pool for the price. It offers enough space for a family of five to move around comfortably without constantly bumping into each other. It’s deep enough to feel like a "real" swim but shallow enough that it isn't intimidating. Just respect the prep work. The difference between a summer of fun and a summer of frustration is entirely in how much effort you put into the ground before the water starts flowing.