Finding the right inground pool covers 20 x 40 can feel like a massive task because, let's face it, a 20x40 pool is a huge area to protect. It's one of the most popular sizes for classic rectangular pools, but its footprint is significant enough that you can't just throw a cheap tarp over it and hope for the best. Whether you're trying to keep the kids safe, block out the autumn leaves, or just stop the sun from eating all your expensive chlorine, the cover you choose makes a world of difference.
If you've owned a pool this size for a while, you know that the sheer weight of a 20x40 cover is something to respect. It's not just about the dimensions of the water; it's about the overlap, the anchors, and the tension that keeps everything tight. Let's break down what actually matters when you're looking for a cover that won't give up after one season.
Why the Safety Cover is the Gold Standard
When most people talk about inground pool covers 20 x 40, they're usually thinking about safety covers. These are the ones that look like a giant trampoline stretched across the water. They are anchored into your pool deck with brass "pop-up" anchors and heavy-duty springs.
The biggest reason people go this route is safety—obviously. If a dog or a child accidentally wanders onto the cover, it's designed to hold their weight. For a pool that's 20x40, that's a lot of surface area where accidents can happen, so having that peace of mind is huge. Beyond safety, these covers just look better. They sit flush with the deck and don't look like a messy pile of plastic held down by water bags.
Mesh vs. Solid Safety Covers
This is the eternal debate in the pool world. If you go with a mesh safety cover, you're choosing something lightweight and easy to handle. Since the mesh allows rain and snowmelt to drain through into the pool, you don't have to worry about a giant, heavy puddle forming in the middle of your yard. The downside? Fine silt and some sunlight get through. This means when you pull the cover off in the spring, your water might be a bit "swampy" and require a few extra shocks to get clear.
On the flip side, solid safety covers block 100% of the sunlight and debris. This keeps your water crystal clear until opening day. However, because water can't drain through, you have to use a cover pump to remove standing water, or you have to choose a version with a small mesh drain panel in the center. For a 20x40 pool, a solid cover is significantly heavier than mesh, so keep that in mind if you plan on taking it off by yourself.
The Role of Solar Covers in the Summer
We can't talk about inground pool covers 20 x 40 without mentioning the "bubble wrap" style solar covers. These aren't for winter protection or safety; they're strictly for heat retention. A pool this large holds about 30,000 to 35,000 gallons of water. That is a lot of thermal mass to heat up.
Without a solar cover, you can lose up to 5 degrees of temperature overnight due to evaporation. By laying a solar blanket on top, you're basically putting a lid on the pot. It traps the heat from the sun during the day and keeps the warmth from escaping at night.
I'll be honest, though: managing a 20x40 solar cover without a reel is a nightmare. Trying to fold 800 square feet of wet plastic while standing on a slippery deck is a recipe for frustration. If you're going this route, invest in a high-quality stainless steel reel. It makes the difference between using the cover every night and letting it rot in the corner of the yard because it's too much work to move.
Measuring for the Perfect Fit
You might think that if your pool is 20x40, you just buy a 20x40 cover. Not quite. Most inground pool covers 20 x 40 are actually sold with a "pool size" and an "actual cover size." For a safety cover, you generally want at least 12 to 18 inches of overlap on all sides. This ensures the anchors have enough room to grab onto the concrete or pavers without being too close to the edge of the water.
If your pool has "true" 90-degree corners, you're in luck. But many 20x40 pools have what they call "radius corners"—basically, they're slightly rounded. If your corners are rounded, you need to make sure the cover you buy is designed to accommodate that. A square-cornered cover on a round-cornered pool will often leave gaps or have weird tension points that can lead to premature tearing.
Dealing with Obstructions
Not every 20x40 pool is a perfect rectangle with nothing around it. Maybe you have a diving board, a slide, or a set of walk-in steps that stick out on one side. If your steps are on the end or the side (often called a "step-out"), you need a cover with a specific extension.
Standard inground pool covers 20 x 40 usually come in options like "20x40 with 4x8 end steps." It's crucial to get this right. If the step section isn't integrated into the main cover, you're leaving a massive gap where leaves can get in and the safety rating goes right out the window.
Installation and the DIY Factor
Can you install a 20x40 safety cover yourself? Yes, but it's a workout. You'll need a rotary hammer drill to sink the anchors into your deck. If you have a concrete deck, it's pretty straightforward. If you have pavers or wood, you'll need special anchors (paver tubes or wood deck anchors) to make sure they don't pull out under the weight of a heavy snow load.
The trick to a good installation is the "cross-tension" method. You start in the middle of the long sides and work your way out to the corners. If you get it wrong, the cover will have wrinkles or "sagging" spots that collect water. For a pool this size, having a second or third person to help pull the straps while you set the springs will save you a lot of back pain the next morning.
Maintenance to Make It Last
A good quality safety cover for a 20x40 pool isn't cheap. You're looking at a significant investment, so you want it to last ten years or more. The biggest killer of these covers isn't the sun or the snow—it's the way they're stored.
When you take the cover off in the spring, don't just shove it into a deck box while it's still wet and covered in worms. Spray it down, let it dry completely, and check for any small holes. Use a patch kit immediately if you see a tear. Also, make sure you store it in a heavy-duty bag that rodents can't get into. Mice love nesting in pool covers, and they will chew through several layers of mesh in a single winter, leaving you with a cover that looks like Swiss cheese.
Final Thoughts on Choosing the Right One
At the end of the day, the best inground pool covers 20 x 40 are the ones that actually get used. If a cover is too heavy or too annoying to put on, it's going to sit in the garage while your pool fills up with leaves.
If you live in a place with heavy winters and lots of trees, a mesh safety cover is almost always the winner. It's the best balance of safety, durability, and ease of use. If you're just trying to keep the pool warm for an extra month of swimming in the fall, a thick 12-mil or 16-mil solar cover with a sturdy reel is the way to go.
Whatever you choose, just remember that a 20x40 pool is a big responsibility. Protecting that water keeps your maintenance costs down, your chemicals balanced, and most importantly, keeps your backyard a safe place for everyone to hang out. It's one of those "buy once, cry once" situations—get a high-quality cover now, and you won't be worrying about it for the next decade.