Recent Odyssey data indicate water ice within centimeters or meters of the Martian surface over wide latitudes. A significant finding in itself, this has much broader applications. This paper applies water phase physics to Odyssey, Viking and Pathfinder data to make a case for the availability of liquid water at the planet’s surface. Liquid water, possibly in biologically significant quantities, is predicted at least diurnally over broad reaches of Mars, including the two Viking landing sites where the Labeled Release (LR) life detection experiment obtained positive signals. Moreover, the data argue strongly against any putative oxidant in the Martian soil that many have assumed was responsible for the LR positive responses. The recently published theory, that currently occurring changes in ravines observed on Mars are caused by flows of solid carbon dioxide rather than liquid water, are shown to be irrelevant to this interpretation of the Odyssey data. The paper concludes that the Odyssey data lend further strength to the author’s claim that the 1976 Viking LR results are of biological origin, and warrant his proposal to send a chiral LR experiment to Mars as an unambiguous way to end the controversy.