Drains start off in jugs (5)
I believe the answer is:
ewers
'jugs' is the definition.
(ewer is a type of jug)
'drains start off' is the wordplay.
'drains' becomes 'sewers' (sewer is a kind of drain).
'start off' means to remove the first letter (the start of the word is taken off).
'sewers' with its initial letter removed is 'EWERS'.
'in' acts as a link.
(Other definitions for ewers that I've seen before include "Water jugs" , "Vase-shaped jugs" , "Pitchers" , "Jugs thrown into sewer" , "containers" .)