Some water — sort of service needed by home (5)
I believe the answer is:
inlet
'some water' is the definition.
(inlet is a kind of water)
'sort of service needed by home' is the wordplay.
'sort of service' becomes 'let'.
'needed by' means one lot of letters go next to another.
'home' becomes 'in' ('he's home' can mean 'he's in').
'let' put after 'in' is 'INLET'.
(Other definitions for inlet that I've seen before include "Gulf" , "A small creek or cove" , "Small area of sea" , "Means of entry" , "Coastal feature" .)