I just called my attorney, and it turns out there is no known law against building an outdoor swimming pool out of an old shipping container. I should have made that call a few years ago, though, since Modpools has now beaten me to the market.
Modpools’ proprietary methodology allows them to “utilize the structural rigidity of a modified shipping container to provide end users with a relocatable hot pool” that can be used all year round thanks to efficient heating methods. Temperature, built-in jets, and lighting controls can also be accessed through your smartphone, and the pools can be converted into hot tubs and vice versa within minutes (or instantly using special dividers).
See some nice footage of how Modpools look in the video below, and check out the product’s official site here, where prices start at just under $27,000 and up. Now if you’ll excuse me, I need to call my attorney again. I think I have a good idea involving shipping containers as cryogenic freezers.