In case of a leak, you should know exactly where to find your whole house shut-off valve so you can turn off the water, and avoid additional damage until repairs can be made.
In the Denver area, it’s typically in the basement, or in the front of the home. Other places to look are in the garage, a mechanical room, or utility area. You will know you found it because it features either a lever style ball valve, or simple gate valve. The lever style takes a simple quarter turn while the gate valve will typically require multiple turns to completely stop the supply of water to your home.