In times when you will be gone for a longer period, such as a vacation, you will need to close the gas line from your house, as a safety precaution. You may find out that knowing how to close the gas line can be a life saving information. The most commonly fuels used are propane and natural gas prom public utility.
Locate the gas line that enters the house from the outside, probably back of the house. Normally you will find a meter and a cut-off valve installed at the spot where the main line enters the house. Another location for a valve can be the ground floor or basement.
Use an adjustable wrench on the valve control. That can be either a lever in case of a natural gas line or a corrugated knob in case of propane. The lever must be rotated clockwise to a 90 degree angle until it is completely turned off and the knob must be turned at its maximum possible level.