A pool house is a remarkable structure whose very design speaks to the lifestyle particulars that most characterize you as an individual.
The structure is much more than a decorative building next to your pool.  Fully functional capabilities are built into each of these structures ranging from accommodating basic activities to providing an individualized forum for luxury pursuits.  

A basic pool house design contains restrooms and changing rooms for people using the pool.
The most important thing this does for you is provide swimmers with a place to change clothes without having to track wet feet back into your house.  Showers can also be built into these rooms so people can rinse off after a swim.

A slightly larger structure could be built to include a storage area.  Pool furniture can be brought in from the elements and stored here. You can also store lawn, garden, and pool maintenance supplies in this area much like you would in a shed. 

A larger pool house can function as the ideal guest quarters for visiting relatives who come to spend their vacation with you.  
No matter how much you love your relatives, accommodating an extended summer stay or holiday visit in the spare room of your home can cramp your lifestyle.  However, you can give yourself the space you secretly long for and treat your loved ones to the time of their lives.  Putting them up in a private lodging that overlooks your custom swimming pool and patio will make them truly feel like they are on vacation.  A fully furnished kitchen replete with all major appliances, full climate control, and a living room area much like that of a small condominium will make them feel like they are truly in a home away from home.

If you do not intend to offer extended stays to guests, but would prefer a more private and practical floor plan for your pool house, consider a home gym right next to your custom pool. 
Nothing beats a hard workout in a gym and a swimming pool.  Your gym can contain the full litany of all you require to get your cardiovascular and muscle toning exercise.  Floor plans can be created that allow for the positioning of treadmills, exercise bikes, exercise machines, and free weights.  The best thing about this is the pool is only a few steps away.  A poolside gym like this will also have showers so you can change into day clothes after a good swim and hard work out. 

You can use your facility as a luxury spa to give it year-round functionality.
Although we have relatively warm winters compared to other parts of the United States, the chill factor of the humidity makes swimming in a open pool during the winter uncomfortable to most people.   This can be overcome by building a hot tub or spa inside your pool house.  Here, you can relax in warm, circulated water and have the comfort of a climate controlled enclosure all around you.   

If you intend to hold outdoor dinner and cocktail parties, invest in a pool house that has a built-in outdoor kitchen, wet bar, home theater, and dining room.
Here, you can prepare meals and serve your guests their favorite drinks without ever having to go into your house.   You can dine at an indoor table, or take the meal outside to an outdoor dining area.  After dinner, guests can choose between poolside activities or their favorite movie in your fully furnished home theater.   The combination of fine food, water sports, ready drinks, and state-of-the-art technology will make your summer parties the envy of your neighborhood.