湯ゆを沸わかして水みずにする

expression

wasting one's efforts; rendering one's efforts futile

Idiomatic expression literally meaning 'to boil water and turn it into water', used to describe doing something pointless or self-defeating.

• せっかく作つくった資し料りょうを全ぜん部ぶ消けしてしまっては、湯ゆを沸わかして水みずにするようなものだ。

  Deleting all the materials you worked so hard to create is like boiling water only to turn it back into water.