It's Utah. You know, Mormons. The bit about them having huge families is real.

With one kid or wife per bedroom and 1000sqft for kitchen/dining/whatever, you have room for 28. (4 wives, 6 kids each) Making the non-bedroom part of the house more luxurious and adding a bathroom to each bedroom, you have room for about 16. You can hit that even without polygamy.

He may be counting a large garage. That could be 1000sqft by itself, so knock off 3 or 4 bedrooms.