Formal — to staff
Ryokan · Onsen
You
すみません、この露天風呂のお湯は自分で調節できますか？
すみません、このろてんぶろのおゆはじぶんでちょうせつできますか？
Excuse me, can I adjust the water temperature of this open-air bath myself?
Romaji: Sumimasen, kono rotenburo no o-yu wa jibun de chōsetsu dekimasu ka? / Reply Romaji: Hai, kochira no rebā de kasui dekimasu. Sekken wa naka ni mochikomanai de kudasai ne.
Reply
はい、こちらのレバーで加水できます。石鹸は中に持ち込まないでくださいね。
はい、こちらのレバーでかすいできます。せっけんはなかにもちこまないでくださいね。
Yes, you can add water with this lever. Please don't bring soap inside (the bath water).
Gesture & etiquette
Point at the lever/faucet near the bath. Show a polite, inquisitive expression.
Do not put soap or shampoo into the bath water itself; always wash thoroughly outside the tub first. Do not use the bath with swimwear unless specified as a mixed-gender, swimwear-required onsen.