Set up H2O around rear of chalet? Absolutely (5-2)

I believe the answer is:

right-ho

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'rear of chalet? absolutely' is the definition.
I know nothing about this answer so I cannot judge whether it can be defined by this definition.

'set up h2o' is the wordplay.
'set up' becomes 'right' (right is a kind of set. I am not sure about the 'up' bit.).
'hio' becomes 'ho'.
'right'+'ho'='RIGHT-HO'

'around' acts as a link.

Can you help me to learn more?

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