Being the other way up makes water escape slowly (4)
I believe the answer is:
seep
'escape slowly' is the definition.
(to seep is to leak or escape slowly)
'being the other way up makes water' is the wordplay.
'being the other way up' is a reversal indicator (in a down clue, letters go up).
'makes water' becomes 'pees' (to pee is to make water or urinate).
'pees' in reverse letter order is 'SEEP'.
(Other definitions for seep that I've seen before include "Flow or leak slowly" , "Leak slowly, ooze" , "Come out slowly" , "Ooze, percolate" , "dribble away" .)