Taps in expensive rental run with water periodically (12)
I believe the answer is:
steeplechase
'run with water periodically' is the definition.
I can't tell whether this defines the answer.
'taps in expensive rental' is the wordplay.
'taps' becomes 'ch' (cold and hot taps).
'in' indicates putting letters inside.
'expensive' becomes 'steep' (I've seen this in another clue).
'rental' becomes 'lease' (synonyms).
'steep'+'lease'='steeplease'
'ch' put into 'steeplease' is 'STEEPLECHASE'.
Can you help me to learn more?
(Other definitions for steeplechase that I've seen before include "Horse race with jumps and ditches" , "run?" , "Race over fences" , "Race with obstacles to be jumped" , "Running event over hurdles and water jumps" .)