What's the noun for syphon? Here's the word you're looking for.
siphon
A bent pipe or tube with one end lower than the other, in which hydrostatic pressure exerted due to the force of gravity moves liquid from one reservoir to another.
“A loud sucking noise in the piping of a fixture indicates that there is a siphonage action which needs correction.”
“The port protector caps have a wick-type design to assure water passage through the siphonage drain lines.”
“Thus, students often have a difficult time predicting conditions that will result in, or prevent, drinking water hazards from back siphonage or back pressure.”
