Picked up taps oddly found in outbuilding — they may need plumbing (6)
I believe the answer is:
depths
'they may need plumbing' is the definition.
The definition suggests an adverb but the answer is not.
'picked up taps oddly found in outbuilding' is the wordplay.
'picked up' shows that the letters should be reversed in order.
'oddly' means one should take alternating letters (letters in odd-numbered positions).
'found in' means one lot of letters goes inside another.
'outbuilding' becomes 'shed' (shed is a kind of outbuilding).
The alternate letters of 'taps' are 'tp'.
'tp' put into 'shed' is 'shtped'.
'shtped' back-to-front is 'DEPTHS'.
Can you help me to learn more?
(Other definitions for depths that I've seen before include "Profundities, seas (fig.)" , "Distances from the top downwards" , "Demoralisation" , "Distances downward" , "Lowest levels" .)