Empty the sink, initially after bath floods (6)
I believe the answer is:
spates
'floods' is the definition.
('spate' can be a synonym of 'flood')
'empty the sink initially after bath' is the wordplay.
'empty' means to remove the middle letters.
'initially' says to take the initial letters.
'after' says to put letters next to each other.
'bath' becomes 'spa' (I've seen this in another clue).
'the' with its centre taken out is 'te'.
The first letter of 'sink' is 's'.
'te'+'s'='tes'
'tes' after 'spa' is 'SPATES'.
(Other definitions for spates that I've seen before include "Sudden forceful flows" , "Floods" .)