We just found that our house has some sort of partial clog in it. Our floor drain is backing up when we run the house water. It is under our basement utility sink. I ran the utility sink water and it eventually backed up after a few minutes of running. It drained back down and when it got slightly past the floor level I had by wife run the main floor bathroom sink. This caused it to back up again. Does anyone have any ideas of what could be causign this? My thought is that I have a partial clog in our house drainage, but want to get some input before we call a plumber. Thank you.