Surface water on Mars, even brief, seasonally appearing surface water, would seem unlikely. The planet is basically a desert, and the low atmospheric pressure means water would vaporize quickly. Yet, water flows may happen. This belief is based on observations from NASA's Mars Reconnaissance Orbiter. Dark features that look like the signature of water flows appear every summer and fade every winter. It's not 100% certain this is from water, but no one has an alternative yet. Likewise, this does not mean there's life on Mars, but every discovery that increases the estimates of Martian water makes astrobiologists more hopeful.
NASA Administrator Charles Bolden: "NASA's Mars Exploration Program keeps bringing us closer to determining whether the Red Planet could harbor life in some form, and it reaffirms Mars as an important future destination for human exploration."
COMMENT: I can't help asking if Mr. Bolden forgot, or wants us to forget, that there is no record of him protesting when his boss killed our program to put humans on Mars.