How would you get enough water on Mars?
A thirty mile diameter crater with a mile thick glacier is a starting point.
There is plenty of water on Mars. There was an article last week about a huge crater full of ice many miles deep, with snow around the crater rim. The water is there for the taking.
Bigger problem is the atmosphere, toxic to humans and non-breathable. And the lack of food, and the challenges of trying to grow anything in that sterile toxic atmosphere.
The more we look at Mars, the more water we find. It’s just not splashing around on the surface. There is certainly no shortage...
https://en.wikipedia.org/wiki/Water_on_Mars#Subglacial_liquid_water
Water along with hydrocarbons are among the basic building blocks of the universe. It’s everywhere.