diagnose

I believe they go to the second floor kitchen and bathroom. I am looking to buy this home. I usually fix things myself. Is there any tests to perform?

This past winter I starting noticing a LOUD thudding noise that vibrates my whole house. At first it would only last 15 - 20 seconds. As it was seemingly coming from my basement where all the mechancial "guts" of my home are, my first guess was that it was my hot water heater vibrating from...