Underground drain (5)
I believe the answer is:
sewer
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">underground drain</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for sewer that I've seen before include "Pipe to carry away waste matter" , "Channel to carry away waste water and matter" , "Drain - seamstress?" , "Main drain" , "Tailor" .)