Abstract: Described herein are systems and methods for liquid phase separation for fuel tanks and other vessels. Particularly, aspects of the present disclosure are directed to a backpressure regulator configured to open when pressure of a mixture upstream of the backpressure regulator exceeds a predetermined setpoint and a hydrophobic membrane upstream of the backpressure regulator and downstream of a first conduit. The predetermined setpoint may be determined by at least a bubble point pressure of the hydrophobic membrane. Additionally, the backpressure regulator may be fluidically connected to and downstream of the first conduit, and to at least one pump operably connected to and upstream of the first conduit and the hydrophobic membrane may be fluidically connected to and upstream of a second conduit. The backpressure regulator may be fluidically connected to and upstream of a third conduit and the third conduit may be downstream the first conduit.