To say "Hello, please give me the water" in Japanese, you would use こんにちは、水をください (Konnichiwa, mizu o kudasai). This phrase combines こんにちは (konnichiwa), meaning "hello" or "good afternoon," with 水 (mizu), meaning "water," and ください (kudasai), a polite way to say "please give me." It’s a courteous expression suitable for formal or semi-formal situations, such as asking for water in a restaurant or someone's home. For more casual contexts, you could say 水ちょうだい (mizu choudai), which conveys the same meaning but in a friendlier, informal tone.