Locate the main water service pipe into your house (probably in the front at the basement level). You will see a gate valve on the pipe. If you know you have leaks you can shut off all water in your house with this valve. You may wish to paint the valve so it is easy to find in an emergency.
In An Emergency
You can shut off all water to your property by finding the water meter box (usually at the street or sidewalk).
Open the cover with a long screwdriver or specialty tool.
If this box is inaccessible or you cannot find it, call your local water department.
Be sure to identify this box and the water valve inside before the need to use them arises.
Inside the water meter box, you will see a valve that is similar to the valve on your gas meter.
Turn it just the same as your gas valve.