Casual to Staff
Convenience · Store
カップ麺にお湯を入れてもいいですか？ (今すぐは食べません) — Can I put hot water in my cup noodles? (I won't eat it right away.) (Convenience · Store, Casual to Staff, JLPT N5)
You
カップ麺にお湯を入れてもいいですか？ (今すぐは食べません)
かっぷめんにおゆをいれてもいいですか？ (いますぐはたべません)
Can I put hot water in my cup noodles? (I won't eat it right away.)
Romaji: Kappumen ni oyu o irete mo ii desu ka? (Ima sugu wa tabemasen) / Reply Romaji: Hai, dōzo. Achira no kyūtōki o goriyō kudasai.
Reply
はい、どうぞ。あちらの給湯器をご利用ください。
はい、どうぞ。あちらのきゅうとうきをごりようください。
Yes, please. Please use the hot water dispenser over there.
Gesture & etiquette
Point to the cup noodles, then make a pouring motion.
While you can ask for hot water, it's generally expected that you'd eat it in the store's eat-in space if available, or take it away to eat soon. Specifying 'not right away' clarifies intent, but some stores might subtly discourage it if it ties up their hot water dispenser for a long time without immediate consumption. It's usually fine though.