To have liquid water on Mars, you must raise the global temperature by 25%. This can be done buy researching the Greenhouse Mars tech in the terraforming column and building some GHG factories. It will take 500 sols for one factory running 3 shifts to raise the temperature to 25%, so you'll certainly want to have more than one running. You can also raise the temperature with the Core Heat Convector, which is unlocked further down the Terraforming column, and through various other techs, breakthroughs, and special projects.
You will also need to research Lake Crafting in the terraforming column. Once you do, build a lake using the Terraforming section of the Build tool. Note that building a "Small Lake" won't get you the achievement. I got it with a "Lake." Whether it will unlock with a "Large Lake" or "Huge Lake," I don't know. You must also connect your Lake to a pipe with a water supply.