Fairly extensive, but to what degree is hard to tell. Tank was on the main floor. Leaked down through the floor and was coming out of the fixture housings in my basement. There are a few random water spots on my ceiling in the basement. Seeped outside of the top of my basement door, where the concrete meets the wood foundation. On the bright side, my house isn't completely leveled, and most of it stayed on one side of the basement and made its way outside. Not all of it, im sure. Sent from my SM-G998U using Tapatalk