Agitate for the right to fresh running water (5)
I believe the answer is:
rouse
'agitate' is the definition.
(I know that agitate can be written as rouse)
'for the right to fresh running water' is the wordplay.
'the right' says to take the final letters (the letter on the right of the word).
'to fresh running water' becomes 'ouse' (I can't justify this - if you can you should give a lot more credence to this answer).
The final letter of 'for' is 'r'.
'r'+'ouse'='ROUSE'
Can you help me to learn more?
(Other definitions for rouse that I've seen before include "Stir up; excite" , "Cause to become awake" , "Move" , "Cause to wake up and come alert" , "cause to wake or to become active" .)