The first thing to do to shut off the main water line is to locate the actual valve to the line. The water line valve is normally located at the lowest point of the property closest to the street. Here in the Chicagoland area, the main water line shut offs are normally placed in the basement closest to the street. After locating the shut off, you must turn it off. If it is a gate valve turn the circular handle to the right. Righty Tighty. If it is a ball valve shut off you must turn the valve lever into the perpendicular position.