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What is the Average Size of Residential Inground Swimming Pools? Get ALL the Details Here

Luxury home with an infinity pool that's integrated with a custom spa.

There’s an old joke told among accountants, lawyers, and other specialized professionals that when a client asks a question that they don’t know the answer to, the best answer to give is, “Well, that depends.” This answer is meaningless, of course, and it might bewilder the client, but it does give the professional time to find the right answer. However, “it depends” might also be the best answer when someone asks the average size of a residential inground swimming pool, too. In fact, in the case of an inground swimming pool, it’s probably more apropos to give this answer, since “average” can be based on so many different factors, all of them important.

Related: Is Installing a Swimming Pool Really Worth It | Luxury Swimming Pools | Swimming Pool Ideas | Swimming Pool Cost | Top Swimming Pool Builders

People and Locations Differ

An in-ground swimming pool with chrome handrails and puzzle paving.

It should come as no surprise that depending on where pool installation is to take place, the pool cost will differ considerably. For better or for worse, this means that what the word “average” means will vary, as well. The truth is that the average cost for nearly any construction project can mean virtually whatever you want it to mean. One important factor in the cost of inground pool installation is what a pool builder is paid to do. This should come as no surprise to anyone who has ever shopped for a new inground pool, a job that usually begins by selecting what you want from a pool builder’s sample book.

All it takes is one look at a sample book to discover a dizzying array of pool shapes. Homeowners can choose from a plethora of pool shapes, from a round pool, to a rectangular pool, to an oval pool, to a kidney-shaped pool. Then, there’s also possible pool designs. Do you like the piano or guitar? Piano-shaped and guitar-shaped pools have been created in the past, and they can certainly be made again. Do you have an initial? Initial-shaped pools have been created, as well. Do you have a logo? Logo-shaped pools have been created, too! Do you enjoy football or baseball? Football and baseball pool shapes are a dime a dozen when it comes to backyard pools. The good news in this is that as much flexibility as there is available when it comes to determining shape of an inground pool also applies to pool size.

Also influencing the average pool shape is its location. In locations where there is more room for an inground pool, pools are often much larger than more urban locations. Take, for example, a metropolis like Los Angeles, where space for a pool is often considerably smaller. However, when money isn’t an issue, the only thing that can hold an owner back when it comes to pool size is the square footage of the area to be filled.

Small, Medium, Large, and More Pool Sizes

Oval shaped pool on a lush green park with brick decking.

The truth is that pool contractors are amazingly adept at building pools wherever an owner wants one, regardless of the desired pool shape or size, or the shape and size of the pool location. That said, the average size of a rectangular pool is 10 feet by 20 feet at the low end of the scale, to 20 feet by 40 feet at the larger end. The primary dictate of a pool’s size is its intended use. A pool that is intended for use primarily by children has a size that would be significantly smaller than one designed for use primarily by adults. When a pool is intended for use by both adults and children, the pool size is usually larger, enabling the creation of a more shallow end for use by children. Institutional pools, such as those found at hotels, apartments, condominiums, and other similar places, solve the problem of pool size for multiple users by creating a smaller, separate pool for children.

The primary concern when it comes to pool size is estimating how many people will typically use the pool at any given time. A single person who does not often host guests would not require a pool of the same size as one a larger family with a lot of friends they entertain on a frequent basis would. It never fails: many people who say that they would never use a pool are often the first to take a swim when any and all occasions present themselves to do so.

Specialty Pools

Pool size is also an appropriate consideration to remember when considering a specialty pool. Specialty pools include pools such as the traditional lap pool, which is often 10 feet wide by 50 feet long. Most lap pools are only about four to five feet deep, with the same depth running the entire length of the pool. This depth is typical because of what this type of pool is used for: swimming laps.

If this is too much for a budget, it’s also possible to install a tethering system into a pool, which makes it possible to create a lap pool out of nearly any sized pool.

Another specialty pool that many future pool owners consider is a therapy pool, which takes the form in most cases of a Jacuzzi or a spa pool. As small as these are normally, they do take up some room, either by themselves as a stand-alone or as part of a traditional pool. Of course, therapy or spa pools are usually not very large, but are typically small pools. On average, these smaller pools measure 7.5 feet by 17.5 feet, though they can be larger.

Filling a Pool

Filling the swimming pool with clean water.

Another factor for potential pool owners to consider when determining pool size is the amount of water that will be needed to fill it. There are other factors to consider, too, such as pool depth. A smaller pool with more depth could cost the same or more to fill as a larger pool that is shallow.

Another question arises for future pool owners, as well: how much work and money will it take to maintain the pool? The larger a pool is, the more it costs to maintain. This is true in terms of not only the time and effort it takes to clean a pool, but also if you choose to use a filter and/or other automated machinery that operates constantly. Machinery like a pool pump or filter will cost more when maintaining a larger pool than it would when maintaining a smaller one. Pool owners must also remember periodic acid washing and other heavier pool maintenance issues. The best adage to keep in mind when it comes to pools and pool maintenance is this: more costs more. When considering the pool size you want, it’s important to keep all these factors in mind, especially pool maintenance costs, as they are more long-term.

Unfortunately, whenever most people talk about the size of the pool they want, they usually describe a large pool. The trouble with this is that most people don’t usually think much about what they are describing, or how often or widely the pool will be used. On the other hand, also, nobody ever turned down the opportunity to use a swimming pool only because it was too small.

Water Capacity

A pool’s capacity in gallons depends on its total area and its average depth. A 12 by 24-foot rectangular pool with an average depth of five feet will hold approximately 10,800 gallons of water. A 16 by 32-foot pool with the same depth will hold about 19,200 gallons, and a 20 by 40-foot pool will hold 30,000 gallons of water.

What About Pool Depth?

Underwater shot of the swimming pool.

Another important question to consider when discussing the average size of an inground pool is the its depth. Pool depth depends largely on who will be using it as well as what they will be using the pool to do. Pools that are to be used primarily by children should have a shallow end with a depth no deeper than three feet. The depth of a pool that is intended for recreational use by both adults and children should have shallow-depth sections at both ends and a middle that does not exceed five feet in depth. A pool that will be used primarily for swimming laps and other fitness uses should not exceed four or five feet in depth for the entire length of the pool.

If you are planning to build a pool that will be used for diving, these pools must be much deeper in the areas where diving is allowed. Minimum diving depths vary depending on the size of the pool and the type of diving equipment installed. Diving equipment, like a diving board, typically requires depths that can range from 7.5 to nine feet. It also matters if there is a diving board present, as opposed to allowing diving from the edge of a pool. This is because the area under a diving board should be deeper than that allowed for edge diving. So, diving pools are typically much deeper than other types of pools, as they should be.

What About Decking?

Lap pool on a backyard with wood decking.

One feature that almost no one ever thinks about when determining pool size is the decking surrounding it. However, pool decking is an incredibly important part of building a pool, and an important thing to factor into pool cost.

Pool owners will most likely use the deck area more often than they use the pool itself. Pool decking is used for furniture, for lounging, and for moving around the pool on land. A pool deck should be large enough that all furniture is at least 30 inches from the edge of the pool, and all walkways must be at least three feet wide. If you plan to have any activities available around your pool, more space will be needed to accommodate those, as well. Deck games and other activities often take place around or near a pool, so allowance much be made for this required space. This is also true for those who want features like a barbecue grill and/or other amenities.

Frequently Asked Questions About Average Pool Size

What is the average inground pool size?

The average size of an inground pool depends on many different factors, such as pool shape. A rectangular pool typically measures anywhere from 10 by 20 feet to 20 by 40 feet. Therapy pools tend to be smaller pools than pools with other uses, measuring about 7.5 by 17.5 feet.

What is the typical shape of the average inground pool?

Inground pools can come in any number of shapes. They can be rectangular pools, round pools, kidney-shaped pools, or any custom shape desired by the pool owner. However, rectangular pools tend to be the most popular inground pool shape, while the average above ground pool tends to be round.

I don’t have a large outdoor space. Can I still build an outdoor pool?

Usually, the answer is – yes, you can! Pool builders are incredibly skilled when it comes to locations, like backyards, that are small and/or oddly shaped. Chances are, with the right pool builder and pool design, you too can add a pool to your outdoor space at home!

Final Thoughts

When it comes to pools, the government is also involved in pool construction. There are government rules, regulations, ordinances, etc. when it comes to residential pools. Because pools can pose not only a safety concern, but can also be an (attractive) nuisance, local governments often impose ordinances with all sorts of different requirements for pools. This includes strict requirements for things such as fences surrounding pools, to keep children out and safe.

All said, the average pool size might be bigger or smaller than average pool size for another pool owner in a different neighborhood or location. These are just a few of the most common questions to ask when determining what pool shape, size, and depth are desired and/or possible.