A water park is an amusement park that features water play areas, such as water slides, lazy rivers, or other recreational bathing environments. The largest indoor water park in the United States is the Kalahari Resort in Wisconsin. It opened in May 2000.
There are more than 1,200 water parks in North America. The largest indoor water park in the United States is the Kalahari Resort in Wisconsin. It opened in May 2000.

Source: https://prezi.com/tlmp74baf1k4/there-are-more-than-1200-water-parks-in-north-america/