You're not right. Actually, your natural feeling is right. Try to follow your natural feeling more as that's the best way to speak English is how it feels, rather than what's correct, chances are that if you're starting to be able to speak fluently you're probably right when it comes to what feels natural.
the water has been cold
Is actually incorrect because you use was when it's the main verb of the sentence, and you use has been when it is not the main verb of the sentence.
The water was cold
In this case was is the main verb
The water has been gettingbecome cold
In this case gettingbecome is the main verb