Abstract: A self-regulating vacuum still (8) has a fluid reservoir (10), a boiler (28), a vapor separator (46), a condenser (33), and a condensate reservoir (58). The boiler (28) receives fluid from the fluid reservoir (10) in liquid form and heats the fluid to generate fluid vapor, preferably using evacuated solar tubes (44). The vapor separator (46) receives the fluid vapor from the boiler (28) and separates entrained moisture. Preferably a packing (50) is provided by structured wire mesh which is disposed in a vapor outlet (49) from the vapor separator (46). The condenser (33) receives the fluid vapor from the vapor separator (46), and cools the fluid vapor to a condensate. The condenser (3) has a collection section (34), a condensate section (35) and an outlet (16) which is proximate to the collection section (34) and the condensate section (35). An airlock (20) is connected to the outlet (16) for venting air and fluid vapor from the condenser (33) when a preselected pressure is exceeded.