Japanese for dual flush toilet

Question

What's the Japanese for dual flush toilet, a flush toilet that allows you to choose either a large flush (大) or small flush (小)?

Google translate suggests "デュアル水洗トイレ" (katakana for "dual" plus "flush toilet"), but the Japanese Wikipedia article on flush toilets doesn't have "デュアル" in it, nor does the Japanese Wikipedia article on toilets in Japan (a google search for オーストラリアの便所 didn't help, either). jisho.org doesn't have anything matching "dual flush" or any relevant matches using デュアル (and based on this search for dual there's only one katakana form for "dual").

Searching ejje for dual flush toilet just supplied the English language Wikipedia article.

linguee.jp had one match for dual flush: "二重流し水洗トイレ", from Australia's main tourism site.

Maybe there's a semantic gap, because Japan doesn't have many single-flush toilets.

Answer 1

In reality, this is not a very common topic of conversation in Japan because, as you so stated, the dual flush is just the norm here. Every time I see/hear the system mentioned, it is mentioned by a non-Japanese person who has visited Japan.

If, however, you need a term for a possible future discussion on the topic with a Japanese-speaker, you might use one such as 「[大小]{だいしょう}[切り替え]{きりかえ}[式]{しき}」、「大小切り替えタイプ」, etc.

I could not promise that these are the most common ways to describe it as I have never actively talked about it with anyone, but I could promise that at least virtually every Japanese-speaker would understand what you are referring to if you used them.

You could say (and be completely understood) things like:

「大小切り替え式の[水洗]{すいせん}トイレ」

「日本のトイレには『大小切り替えレバー』がついています。」　レバー = lever

Less than 1% of us would understand 「デュアル[水洗]{すいせん}トイレ」 if you trust me. Ask any other native speakers.

Answer 2

Maybe it would help if you share what you need this for. If it's to convey to someone you want to purchase a toilet with both flush types "二重流し水洗トイレ" or 大小切り替えタイプ will get the message across. I'm sure any japanese person will figure out you want a toilet with both flush patterns.

If it was me I would say "大・小水洗付きトイレ" (read ”だい・しょう・すいせんつきトイレ”)

Answer 3

There might be somewhat of a semantic gap, most people won't ever need to use the word, discussion about toilet models would much more concerned about washlets, rather than dual flush.

It seems however that the correct form would be "デュアル水洗式トイレ" rather than "デュアル水洗トイレ" that mostly Chinese sites use, specifically with regard to this http://ja.myecom.net/english/blog/2015/028465/ and this http://www.sekaimon.com/us/71284/Toilets/151176694826/ occurrence.

I've found one case of デュアルフラッシュ in a PDF, but this is usually the transcription of "dual flash", so not recommended