What do you do if you drank 1 liter of non potable water?

Non-potable water is not necessarily dangerous, but it is water that has not been treated for human consumption. It is a term normally used for so-called "reclaimed water," otherwise known as water that has come from a sewer and lightly treated, also otherwise known as toilet water.

Like I said, not necessarily dangerous, but it can make you sick. Slight chance of making you seriously sick. Bigger chance of having a funny taste. 100% chance of grossing you out if you think about it too much, and 150% of making you date-proof for a few weeks if it gets out that you drank poo-water.