So why is the adjective plural? Is the word for water plural already, because it's an uncountable quantity of something? I mean, because you can't count pieces of water.
Not exactly because it is uncountable, not all uncountable nouns have this property. But yes, it's true that מים is plural and has no singular form.
So מים is already plural! I didn't notice, תודה! And yes, the water is soo tasty!