Accidents happen. That being said, are your sure you hit it? Was the water line live? If it's in a basement I am thinking maybe they are just now finishing the basement, meaning that it's possible, probable that the line is valved off somewhere? determine whether the water line is active then you can determine real quickly whether or not you damaged it. Make sure that the line, or valve that feeds this line is open and active. If you don't see anything getting wet, this is a good sign but your not completely out of the woods yet. If you know that water is going into that line, tell everyone in the house to NOT use any water, NO flushing of toilets, no water usage for 15 mins to a half hour, then after you have determined no water is going anywhere, turn the meter off...wait for the 15 mins or so, then turn the water on...if you hear a gush of water going through the meter (provided no body flushed a toilet or opened a valve), you've got problems...