Irrigates (6)
I believe the answer is:
waters
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">irrigates</span>' is the definition.<br/ ><span class="explanation-format__explanation">('water' can be a synonym of 'irrigate')</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for waters that I've seen before include "(Of the mouth) salivates" , "What may be taken at a spa" , "floods" , "Irrigates" , "Sprinkles" .)