Sources of water in Somerset (5)
I believe the answer is:
wells
'sources' is the definition.
(well is a kind of source)
'water in somerset' is the wordplay.
'water' becomes 'well water' (well water is a kind of water).
'in somerset' becomes 's' (I can't explain this - if you can you should give a lot more credence to this answer).
'well'+'s'='WELLS'
'of' acts as a link.
Can you help me to learn more?
(Other definitions for wells that I've seen before include "H. G. . . . . ., science-fiction writer" , "Oil sources" , "Novelist and city" , "Cathedral city; sci-fi writer" , "H.G. - - , writer" .)