"I am drinking water."
Translation:Ich trinke Wasser.
The construction "Ich bin Wasser trinken" exists in colloquial German but it means something completely different, namely 'I am away, drinking water' (this form is occasionally called 'absentive' by grammarians).Depending on where you are in Germany, people may consider it either to be completely normal or rather poor style. So, my recommendation is: you should know what it means, but don't use it yourself. As others already have pointed out: German doesn't have a continous aspect.