This ESA mission has introduced both new measurements and a new way of thinking to the understanding of Mars' water.

The overview paper concludes:-

Conclusion:

The detection and mapping by OMEGA of pristine and altered surface minerals give key clues to decipher the evolution of the Mars environment. Placed in their geological context, they model a profoundly renewed vision of the past Martian climate. 30 years after the pioneering measurements of the Viking landers, the OMEGA orbital near infrared survey indicates that Mars might indeed have hosted, once in its earlier past, conditions favouring liquid water to remain stable over long durations. The sites in which one might search for these potential habitats are not located where the optical images would have led us to consider, that is primarily in relation with fluvial or other water-driven structures. OMEGA suggests that the most favourable sites are those characterized by their mineralogical content of hydrated phyllosilicates. Most of these targets have already been identified. A refined analysis by MRO/CRISM, with a ten-fold higher spatial sampling, greatly increases their characterization. It is our deep conviction that if ever life once emerged on Mars, these phyllosilicate-rich sites are the targets in which future in situ laboratories (NASA/MSL and ESA/ExoMars) have the best chances of finding potential biorelics, at a microscopic scale.

Be careful to read the paper in detail and understand it's conclusions. Mars has been dry and barren for 3 1/2 Billion years, despite localised floods (and I must admit that the evidence is swinging in favour of water/sulphuric acid for these floods)

There are many other excellent papers here, with some good bedtime reading. Please be careful not to quote them out of context and to make clear what is your own interpretive overlay when you discuss these...