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N5Lesson notes · Oct 4, 2026

Water in Japanese: 水みず (みず), お水みず, お冷ひや and お湯ゆ explained

"Water" in Japanese is 水みず (みず), or お水みず (おみず) when you want to sound polite — but Japanese splits water by temperature, so hot water is not 水みず at all, it is お湯ゆ (おゆ).

That one split explains most of the confusion. English has "water" and adds an adjective for hot or cold. Japanese uses a separate word once the water is heated, and a third word, お冷ひや (おひや), for the glass that shows up on your table at a restaurant. This article sorts out which word to use where, how to ask for water without sounding blunt, and why 水みず appears in so many other words.

The basics

How do you say "water" in Japanese?

The word is 水みず, read みず. It is one of the first kanji most learners meet, and it is a plain, everyday noun with no tricky grammar.

水みずを飲のみます。 — I drink water. (polite, neutral) 水みずをください。 — Water, please. (polite, short and direct) 冷つめたい水みずが飲のみたいです。 — I want to drink cold water. (polite, stating a wish)

Use が with 飲のみたい (the thing you want) and を with 飲のむ (the thing you drink): 水みずを飲のむ, but 水みずが飲のみたい. Both are normal.

What is the difference between 水みず and お水みず?

お水みず is the same word with the polite prefix お added. Staff say it to guests, and you can say it when you are asking for something from someone you do not know.

お水みずをお持もちしますね。 — I'll bring you some water. (very polite, a server speaking) お水みず、いただけますか。 — Could I have some water? (very polite, a customer asking)

With friends and family, plain 水みず is the normal choice. You will hear お水みず from a server much more often than you will need to say it, but it is never wrong to use when asking a stranger for a favor.

Why is hot water お湯ゆ and not 水みず?

Because 水みず means water at normal or cold temperature. Once water is heated, Japanese changes the word: 湯ゆ (ゆ), nearly always with the お prefix, お湯ゆ (おゆ). Boiling water is 熱湯ねっとう (ねっとう).

お湯ゆを沸わかします。 — I'll boil some water. (polite, kitchen) お湯ゆをください。 — Hot water, please. (polite, at a cafe or restaurant) お湯ゆが出でません。 — The hot water isn't coming out. (polite, a problem at a hotel or home)

The same logic gives you お風呂ふろ (おふろ, the bath) with お湯ゆ in the tub, and 白湯さゆ (さゆ), plain hot water you sip on its own. If you say 水みず and mean "hot water", people will usually work it out, but it sounds off, a bit like saying "ice" when you mean "steam".

Beyond the basics

What is お冷ひや (おひや) at a restaurant?

お冷ひや is the water a restaurant serves you, usually cold and often with ice, before you order anything. It comes from 冷ひや, an older word for cold water. It is a set restaurant word, so you can use it whether the glass is cold or not.

お冷ひやをお持もちしました。 — Here is your water. (very polite, staff speaking) お冷ひやのおかわりをお願ねがいします。 — Could I have a refill of water, please? (polite, to a server)

In many restaurants the お冷ひや arrives without you asking. If it does not, asking is normal and nobody will think it strange.

How do you ask for water at a restaurant?

Say お水みずをください or お冷ひやをお願ねがいします. The first is direct and fine; the second is a touch smoother because お願ねがいします turns it into a request rather than a command.

すみません、お水みずください。 — Excuse me, water please. (polite, calling a server) お冷ひやをお願ねがいします。 — Water, please. (polite, softer than ください) お水みずを一杯いっぱいいただけますか。 — May I have a glass of water? (very polite, 一杯いっぱい = one glass)

If you want more, use おかわり: お水みずのおかわりをお願ねがいします. And if the ice is the problem, 氷こおりなしでお願ねがいします (no ice, please). When you need to adjust an order after it is already in, the phrases in how to change your order in Japanese work the same way for a drink.

Is tap water 水道水すいどうすい or ミネラルウォーター?

Both words exist, and they name different things. 水道水すいどうすい (すいどうすい) is tap water, the water that comes out of the 水道すいどう (すいどう, water supply). ミネラルウォーター is bottled mineral water, written in katakana because it is borrowed from English.

水道水すいどうすいは飲のめますか。 — Can you drink the tap water? (polite, a traveler's question) ミネラルウォーターを一本いっぽんください。 — One bottle of mineral water, please. (polite, shop or cafe)

The restaurant お冷ひや is normally ordinary water, which is why it is a free default in so many places. If you specifically want sparkling water, ask for 炭酸水たんさんすい (たんさんすい).

Why does the same kanji 水みず have two readings?

水みず reads みず on its own and すい in many compounds. This is the usual pattern: a kanji standing alone or paired with native Japanese words keeps the native reading (みず), while kanji stacked into Chinese-origin compounds use the sound reading (すい).

Word Reading Meaning
水みず みず water
水曜日すいようび すいようび Wednesday
水道すいどう すいどう water supply, tap
水泳すいえい すいえい swimming
水族館すいぞくかん すいぞくかん aquarium
香水こうすい こうすい perfume
水着みずぎ みずぎ swimsuit
水色みずいろ みずいろ light blue
水風呂みずぶろ みずぶろ cold plunge bath

香水こうすい literally means "fragrant water". 水着みずぎ is "water clothes", a swimsuit. 水曜日すいようび is the "water day": the weekday names in Japanese come from the classical elements and heavenly bodies, and 水みず pairs with Mercury (水星すいせい). That is why Wednesday is the "water" day.

What does the kanji 水みず look like?

水みず has four strokes and looks like a stream of drops flowing from a central line. Its shape also shows up as a radical in many water-related kanji, sometimes squashed into three dots on the left, as in 海うみ (sea) and 泳えい (swim). If you see those three dots, the kanji very often has something to do with water.

How does 水みず show up in anime?

Constantly, and usually as a power. The water element is part of the classic five elements (木き火土かど金水きんすい), and anime borrows it heavily.

水みずの呼吸こきゅう、壱いちノ型かた。 — Water Breathing, First Form. (dramatic, a named technique) 水みずタイプには草くさタイプが有利ゆうりだよ。 — Grass types are strong against water types. (casual, a game explanation) 水みず…水みずをくれ…。 — Water... give me water... (desperate, the classic thirsty-in-the-desert line)

The element reading is also common in names: 水樹みずき (みずき) and 水野みずの (みずの) are real names built on 水みず, and a character named with 水みず often has a calm, flowing, or cool personality. That is a storytelling habit, not a rule.

One more phrase worth knowing is 水みずくさい (みずくさい). It does not mean "smells like water". It means being unnecessarily distant or formal with someone close to you, and anime friends say it when someone is being too polite.

水みずくさいぞ、俺おれたち友ともだちだろ! — Don't be so formal, we're friends! (casual, an emotional line)

How do you talk about taste and cold with water?

Water barely has a taste, but people still say it is 冷つめたい (cold), ぬるい (lukewarm) or おいしい (tasty). For more words like these, see Japanese taste words like 甘あまい and 酸すっぱい. And if you are at the register paying for a bottle, how to ask the price in Japanese covers いくらですか.

Common mistakes

  • Saying 水みず for hot water. Use お湯ゆ. 水みず is cold or room temperature.
  • Reading 水着みずぎ as すいぎ. It is みずぎ. The word mixes the kun reading (みず) with 着ぎ (ぎ), so it does not follow the すい pattern.
  • Treating お冷ひや as something you have to order. It is the free default in many restaurants, so asking for お水みず is only needed when it has not come or when you want more.
  • Using お水みず to talk about yourself in casual speech. With friends, 水みず is fine. お水みず from your own mouth about your own glass can sound over-polite.
  • Mixing up を and が. 水みずを飲のむ (drink water), but 水みずが飲のみたい (want to drink water).

The water words by situation

Situation Word Notes
Cold or room-temperature water 水みず the basic word
Polite or asking staff お水みず softer, with お
Water served at a restaurant お冷ひや usually free, often iced
Heated water お湯ゆ also 熱湯ねっとう (boiling)
Plain hot water to sip 白湯さゆ no tea, no flavor
Tap water 水道水すいどうすい from the 水道すいどう
Bottled mineral water ミネラルウォーター katakana, from English
Sparkling water 炭酸水たんさんすい たんさんすい

Practice

Build each answer before opening it. Questions 1 and 2 are a pair: the same liquid, two different words.

1. You want a cup of hot water. Which do you ask for: 水みず or お湯ゆ?

Show answer

お湯ゆ — heated water has its own word. 水みず means cold or room-temperature water.

2. You want a glass of cold water. Which do you ask for: 水みず or お湯ゆ?

Show answer

水みず — this is the pair to question 1. 冷つめたい水みず makes it extra clear.

3. Ask a server politely for water.

Show answer

お水みずをください or お冷ひやをお願ねがいします — both work, and お願ねがいします is slightly softer.

4. What is お冷ひや?

Show answer

The water a restaurant serves you at the table — usually cold, often with ice, and often brought before you order.

5. How do you say "Could I have a refill of water?"

Show answer

お水みずのおかわりをお願ねがいします — おかわり is "a refill" and お願ねがいします makes it a polite request.

6. Read 水着みずぎ aloud and give its meaning.

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みずぎ — swimsuit — it uses the みず reading, not すい.

7. Read 水曜日すいようび aloud and give its meaning.

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すいようび — Wednesday — this is the pair to question 6: here 水みず reads すい, in a Chinese-origin compound.

8. What is the difference between 水道水すいどうすい and ミネラルウォーター?

Show answer

水道水すいどうすい is tap water; ミネラルウォーター is bottled mineral water. The first comes from the 水道すいどう (water supply), the second is a katakana loanword for a bottled product.

9. Which particle goes with 飲のみたい: 水みずを飲のみたい or 水みずが飲のみたい?

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水みずが飲のみたい — が marks the thing you want. 水みずを飲のみます uses を because you simply drink it. 水みずを飲のみたい is also heard in everyday speech.

10. A friend says 水みずくさい. Are they talking about water?

Show answer

No — they mean you are being too formal or distant. It is an idiom for unnecessary reserve between people who are close.

During a trial lesson, ask for お水みず in a restaurant and お湯ゆ at home, and notice why Japanese splits water by temperature.

FAQ

Is お水みず more polite than 水みず? Yes. The お turns plain 水みず into the polite form, and staff use it to guests. With friends and family, plain 水みず is more natural.

What do I say to get warm water, not hot? Ask for ぬるめのお湯ゆ ("slightly cool hot water"), or 白湯さゆ if you want plain hot water to sip. ぬるめ is an easy way to ask for "not too hot." Or just say お湯ゆ and let the server decide, since they will usually give you hot water and you can ask for more cold water to mix.

Do Japanese restaurants bring water automatically? In many restaurants they do, as お冷ひや, before you order anything. If it has not come, お水みずをお願ねがいします is a normal way to ask.

Is the water okay to drink in Japan? Tap water (水道水すいどうすい) is commonly used for drinking, and the お冷ひや at a restaurant is normally ordinary water. If you prefer bottled, ミネラルウォーター is easy to find, and 炭酸水たんさんすい is the word for sparkling water.

Why is Wednesday the "water day"? The Japanese weekday names are built from sun, moon and the classical elements and planets. 水曜日すいようび matches the water element and the planet Mercury (水星すいせい), which is also called "water star" in Japanese.

Vocabulary from this article

Tap the block to select all of it, then copy. In Anki: File → Import, note type Basic, separator Tab — the first column becomes the front, the second the back.

水	みず — water
お水	おみず — water (polite)
お冷	おひや — water served at a restaurant
お湯	おゆ — hot water
熱湯	ねっとう — boiling water
白湯	さゆ — plain hot water, sipped
水道水	すいどうすい — tap water
ミネラルウォーター	ミネラルウォーター — bottled mineral water
炭酸水	たんさんすい — sparkling water
水曜日	すいようび — Wednesday
香水	こうすい — perfume
水着	みずぎ — swimsuit
おかわり	おかわり — a refill
冷たい	つめたい — cold
水くさい	みずくさい — distant, too formal with a close friend

I'm Yuuki, a Japanese teacher based in Tokyo. I've taught on italki as a Top 1% teacher and watched over 1,500 anime, so most of the example sentences on this blog come from lines I've actually heard students ask about — including this one, which comes up in nearly every beginner's first few lessons. For practice with feedback, Book a trial lesson · $13, or work through Japanese practice exercises first.

Sources: the author's own lessons and standard reference grammars.

More drills like the ones above, plus a timed JLPT-style mock test: Practice · N5 · Read something at this level: JLPT N5 stories with audio

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