Misplaces spittoon continaing reservoir of waste water (7)

I believe the answer is:

cesspit

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'water' is the definition.
(cesspit is a kind of water)

'misplaces spittoon continaing reservoir of waste' is the wordplay.
'CESSPIT' is hidden within the letters.
But, I am unsure how this is indicated.

Can you help me to learn more?

(Other definitions for cesspit that I've seen before include "Sewage holder" , "Sewage storer" , "Foul and squalid place" , "Sewage receptacle" , "Sump" .)

I've seen this clue in The Irish News.

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