Bit of a shower head in receptacle in a rubbish dump (8)
I believe the answer is:
raindrop
'bit of a shower' is the definition.
(I've seen this before)
'head in receptacle in a rubbish dump' is the wordplay.
'head in' says to take the initial letters.
'rubbish' indicates an anagram (a poor quality or rubbish spelling of the letters).
'dump' becomes 'drop' (I can't explain this - if you can you should give a lot more credence to this answer).
The first letter of 'receptacle' is 'r'.
'in'+'a'='ina'
'ina' is an anagram of 'ain'.
'r'+'ain'+'drop'='RAINDROP'
Can you help me to learn more?
(Other definitions for raindrop that I've seen before include "Water from the heavens" , "Part of a shower" , "One of many in a shower" , "Spot of precipitation" , "Pro-drain (anag)" .)