Considerations When Building an Indoor Swimming Pool

Written by Michael Dean
July 6, 2023

construction worker building an indoor swimming pool

Indoor swimming pools are growing in popularity. And with good reason. There are many advantages to choosing an indoor pool over an outdoor pool, such as swimming 365 days a year, no matter the weather!

Today, I will work through some of the main things you need to consider if you’re considering getting an indoor pool.

Main Takeaways

  • Indoor pools almost always cost more than outdoor pools, as they cost more to install and run.
  • Indoor pool designs need to account for humidity control and ventilation.
  • Outdoor pools require more maintenance because they are exposed to the elements; however, algae can be a big problem with indoor pools.

Advantages and Disadvantages of Indoor Pools

Now let’s look at the good and bad about indoor pools.


  • You can swim year-round
  • Indoor pools require a lot less maintenance
  • You can’t get sun damage
  • You use fewer chemicals with indoor pools
  • Safety
  • Privacy


  • Indoor pools put a lot of humidity into the air
  • Indoor pools cost considerably more than outdoor pools
  • Heating the pool will increase your energy cost

Cost of an Indoor Pool vs. an Outdoor Pool

No matter how you slice it, indoor pools cost more than outdoor pools. They cost more to install, and they will cause your energy bill to go up. If you plan to install an indoor pool from scratch, you should plan on spending around $150,000 – $200,000. That price includes the cost of a standard pool, dehumidifier system, pool house, and decking or patio. The final cost will obviously vary based on the water features you want, materials, and other details.

How the Construction Process Is Different for Indoor Pools vs. Outdoor Pools

There are some significant differences in the construction process of indoor pools vs. outdoor pools. Let’s take a look at some of them.


The first difference between the design of an indoor pool vs. an outdoor pool is that an indoor pool requires a complete HVAC system. Indoor pools create a lot of humidity, so you will need a method to deal with that. Indoor pool designs also have to address proper ventilation and heating.

Another main difference in the design of an indoor pool compared to an outdoor pool is the slope of the deck. With outdoor pools, the deck will slope away from the water. The reason for this is that it keeps debris and runoff water from going into the pool.

Indoor pools are just the opposite. Decks slope toward the pool because they don’t have to worry about water runoff or debris. The inward slope of an indoor pool deck also helps with keeping the water away from the walls. For more on decks, read my pool coping 101 guide.

When it comes to the overall design of your pool, there’s also a difference in the materials used. Builders have more flexibility with indoor pool materials because they don’t have to worry about freezing or thawing.

For inspiration, I compiled a list of my favorite indoor pool design concepts.

Making Sure Your Indoor Pool Has the Right Structural Support

As I mentioned earlier, indoor pools produce a lot of humidity. That means you will need the proper structural support system to handle that. For one thing, you will need plastic vapor barriers behind the walls. This will stop moisture from getting into the structural framing of the room. Some indoor pool builders also use water-resistant drywall called green board in the pool room.

Another thing you need to consider with indoor pools is an equipment room. You are going to need ample space for the equipment. To make sure that you will have plenty of room to work on your hardware, you should take the advice of your pool builder. They will have the best ideas for your space. If you have the option, it’s a good idea to make your equipment room accessible from the outside.

You also have to think about chlorine. If you’ve ever been around a swimming pool, you know the smell of chlorine. Well, with an indoor pool, the smells are amplified. For this reason, you must have a sound ventilation system. You can also use a mineral purifier or Ozonator to help with the smell.

Getting Proper Ventilation

As I just said, proper ventilation is essential to help with the smell of chlorine. But it’s also crucial for humidity control. I recommend keeping the humidity at 50 to 60 percent in your indoor pool room.

As a general rule about indoor pools, you should keep your air temperature two degrees warmer than the water. If you do this, it will keep your humidity and evaporation in control.

One thing worth noting with a ventilation system is that you don’t want to force air across the surface of the pool.

If your dehumidifier blows air over the water, it will increase the levels of evaporation. So instead, you should aim the air toward the outside walls. This will both cut down on the humidity and prevent condensation.

Another thing you can do to reduce evaporation and humidity significantly is to use an automatic pool cover. Believe it or not, a simple pool cover can reduce evaporation by 50 percent.

It’s also important to pay attention to your deck drainage. If you have a lot of puddles around the pool deck, that will contribute to raising the humidity level in the room.

Some people deal with the problem of puddles with a radiant floor heating system. This will help dry them out. And it has the bonus benefit of keeping your feet warm in the winter.

Lighting Options

The lighting options are very different between indoor and outdoor pools. With an outdoor pool, you have plenty of natural sunlight. You can’t say the same when your pool is inside. You can add some light to your indoor pool by adding some windows and skylights. But if you want to enjoy your pool at night, you will also need some additional lighting.

Most people use underwater lights combined with wall sconces. The thing you should avoid is overhead lighting. When you think about how difficult it would be to change light bulbs directly above the pool, you can see why this is a terrible idea. Instead of lightbulbs, a glass ceiling window is a great way to get natural light into your pool area.

If you’re really set on having lights above the pool, I suggest that you think about getting fiber-optic cable fixtures that are easily accessible.

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Main Maintenance Differences with Indoor Pools vs. Outdoor Pools

While there are some similarities in the maintenance required for an indoor pool and an outdoor pool, there are also some significant differences. One of those differences is that you can use an indoor pool throughout the entire year. Unlike outdoor pools, indoor pools don’t require any winterizing.

Generally speaking, outdoor pools require more maintenance because they are vulnerable to contaminants like leaves and dirt. Now that doesn’t mean that indoor pools won’t need to be cleaned; they will. Even with an indoor pool, you should vacuum once a week.

Algae can be a problem in any swimming pool, but it can be a particular problem for indoor pools. Sunlight is an excellent oxidizer. Outdoor pools have the benefit of that sunlight reducing any algae naturally.

Since you don’t get that sun in an indoor pool, you must keep the water balanced. That includes shocking the water regularly. Most people don’t realize it’s even more critical to shock indoor pools. Shocking means raising the chlorine level by two or three times the normal amount.

When you shock your indoor pool, you are releasing contaminants into the air. This is yet another reason that you need a good ventilation system; without that, the pollutants would just fall back into the water.

Even though you don’t have to winterize an indoor pool, it’s a good idea to take a couple of days to shut it down for yearly maintenance. That includes draining the pool and checking the functionality of the pump. It’s also important to service your equipment regularly to avoid breakdowns.

Safety Tips To Remember

Although pools are fun, it’s important to take the proper precautions to keep everyone safe and free from accidents.

Make sure your pool area is completely enclosed and separate from other parts of the house so you can lock the door to the pool and prevent unsupervised swimming if you have children running around.

Speaking of running, no running around the swimming pool! The deck will likely be very wet, so make sure to establish ground rules for your friends and family when using the pool.

Check your pool and area regularly for potential things like glass and electronics that can be a hazard. Glass can greatly damage your pool and line. Make it a point to only use plastic in and around your pool for protection and to avoid danger not only to your pool but to your guests as well.

Finally, consider using some accessories like an automatic pool cover and pool alarm for some extra safety measures.

Frequently Asked Questions About Indoor Pools

Can you build an outdoor pool first and enclose it later?

In short, yes. It is possible but not always recommended. Where possible, planning is crucial to saving time and money. Consider the time to install, increased cost, and potential for damage that comes along when enclosing an outdoor pool.

What accessories should you consider for your indoor pool?

There are a few accessories that you should consider. First, an automatic pool cover is great for added safety and keeping your pool temperature regulated, although that is much easier to do for an indoor pool. Make sure to invest in a pool heater too, an essential piece of equipment to keep your water at a comfortable temperature for swimming all year round. Lastly, on the larger accessories investments, consider some automation around your pool. Automated controls take the hassle out of manually changing settings or simply turning the lights in the pool on.

There are other fun accessories to consider adding to your pool too that are less essential for operating your pool. Music speakers, floaties for drinks, toys, and games.

Do the permits you need to build an indoor pool differ from an outdoor pool?

Your municipality will require some type of permit to build an inground swimming pool whether it is for an indoor pool or outdoor pool. You may only need a residential building permit while others require an electrical permit. This will need to be discussed with your local city or town to find out which type of permit you need. You will need to talk with your homeowner’s association as well if you have one. Make sure to ask your pool builder about any necessary permits, they should be knowledgeable about what is required in your local area.

Any other questions? Feel free to shoot me a note.

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