YOU SAID:
Hello I'm under the watet
INTO JAPANESE
こんにちは、私は水の下にいます
BACK INTO ENGLISH
hello i'm under water
INTO JAPANESE
こんにちは、私は水中にいます
BACK INTO ENGLISH
hello i'm in the water
INTO JAPANESE
こんにちは、私は水の中にいます
BACK INTO ENGLISH
hello i'm in the water
That didn't even make that much sense in English.