A modern fire extinguisher can be stored horizontally. The contents are under pressure, and the angle of storage will not cause the system to leak. Proper fire extinguisher storage includes using the appropriate mounting brackets, and being sure that you do not allow for your fire extinguishers to freeze. It is also proper to be sure to store your fire extinguisher within easy reach of areas where there is more fire danger, such as within easy reach of the kitchen stove, or near the door of your garage.