A diaphragm pressure regulator includes: a body defining a process surface and including: an exhaust port having a discharge opening, and at least one vent void interconnecting the process surface and the exhaust port; and an inlet port, and at least one process void communicating with the process surface and the inlet port; a reference housing including a cavity defining a reference surface and a reference port in fluid communication with the cavity; and a diaphragm disposed between the body and the reference housing, the diaphragm movable between a first position engaged with the vent voids, and a second position wherein the membrane is not engaged with at least one of the vent voids, wherein a dome is defined between the cavity and the reference side of the diaphragm; and wherein the reference housing includes a sump configured to segregate liquid from the reference side of the diaphragm.