It’s not obvious to me, but it seems this picture (Credit: NASA/JPL-Caltech/Univ. of Arizona):
shows there is flowing salt water on Mars:
Using an imaging spectrometer on MRO, researchers detected signatures of hydrated minerals on slopes where mysterious streaks are seen on the Red Planet. These darkish streaks appear to ebb and flow over time. They darken and appear to flow down steep slopes during warm seasons, and then fade in cooler seasons. They appear in several locations on Mars when temperatures are above minus 10 degrees Fahrenheit (minus 23 Celsius), and disappear at colder times.
I guess I should start looking into beachfront property there, it should be cheap.