A collapsible reservoir system is disclosed herein. The collapsible reservoir system includes a first tube pneumatically connected to the collapsible reservoir, and a second tube pneumatically connected to the collapsible reservoir. The second tube is configured to generally remain open in the absence of an externally applied compressive force. The second tube is positioned relative to the collapsible reservoir such that a compressive force applied to the collapsible reservoir can also compress and thereby restrict the second tube. A corresponding method for controlling the pressure of a collapsible reservoir system is also provided.