It may be paid when there's silver in the house (6)
I believe the answer is:
homage
'it may be paid' is the definition.
(as in 'to pay homage')
'silver in the house' is the wordplay.
'silver' becomes 'Ag' (Ag is the chemical symbol for silver).
'in the' means one lot of letters goes inside another.
'house' becomes 'home' (homing is a kind of housing).
'ag' put within 'home' is 'HOMAGE'.
'when there's' is the link.
(Other definitions for homage that I've seen before include "Formal expression of respect" , "Acknowledgment of superiority" , "Dutiful reverence" , "Public honour and respect" , "Public show of respect" .)