Same thing happened to me about a month ago. The main shut off valve before the meter blew right off. It happened at about one o'clock in the morning. Good thing I awoke when it happened because it made a very faint noise. Went to the bottom of the stairs and stepped into water. Went to shut the water off at the meter and no more shut off...just water pouring out of a water service at about 60 plus psi. Had to call the water dept. Of course, they didn't get there for about an hour, then couldn't find the shut off in the yard, so they had to shut the whole street down. No problem...its now after three AM. All dry now and waiting for insurance. BTW, it is a completely finished basement.