Dilutes potential waste product, protecting river (6)
I believe the answer is:
waters
'dilutes' is the definition.
(I've seen this in another clue)
'potential waste product protecting river' is the wordplay.
I cannot quite see how this works, but
'river' could be 'r' (abbreviation) and 'r' is located in the answer.
an anagram of 'waste' is 'wates' which is located in the left over letters.
No letters remain.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for waters that I've seen before include "(Of the mouth) salivates" , "Sprinkles" , "Muddy - - (blues singer)" , "Irrigates" , "What may be taken at a spa" .)