Longo Daegmund is convinced that something in the Staddle town well caused Gar's illness.
'I think there is something wrong with the water in the town well, ${PLAYER}! It certainly smells peculiar, that's for sure, and would explain why Gar has been feeling poorly.
'Could it be that something has gotten into the well and poisoned the water? That would be terrible, but it seems likely!
'Go and tell Lily Underhill -- we can't have people drinking from the well until we can clean the water somehow! Lily lives over yonder, east of Boggs' Farm.'
Lily Underhill's home is east of the town square, past Boggs' Farm.
Longo Daegmund, worried about the Staddle town-well, asked you to speak with Lily Underhill.