I had a similar experience with a home I purchased recently. I had the water turned on upon closing and it started raining in the living room! The person who had tried to flip the house before me (had no clue what they were doing and got in way over their head) had tried to do the plumbing in the upstairs bathroom themselves. They had pipes going up, over, down, over, up again, etc. And to top it off, they hadn't even connected the water supply to the toilet (hence the rain in the living room). Needless to say I was calling
San Francisco Plumbers immediately. What a mess!
If they had simply gotten a plumbing for dummies book, or done a search on google, or gotten on a forum like this, I wouldn't have had this headache and pain in the wallet to deal with!