Is it your fresh water tank drain?
Is there a small valve on the end? If so try to close it.
Just a shot in the dark...a pic might help.
BTW: Welcome to the forum from Upstate NY.
Craig & Cath
2018 2902WS Rockwood Ultra Lite (with tons of Mods)
2017 Ford F250 Lariat, 6.2 gas (2022 F250 Lariat 7.3 gas with 10 speed Xmsn on order)
Equalizer Hitch w/ 4-Point Sway Control
Days camped since 2015(retirement): 1050