Keystone Laredo M-290SRE City water compartment

[Mgdg]

My 2014 Keystone Laredo M-290SRE has a compartment with 3 inlets, one is the City water connection on the back wall and 2 more connections on the right side wall. I assume one is for black tank clean out. A valve is near the bottom of the side wall what is that for ?? Thx

[Terry W.]

Just a guess with out a picture to look at is that it's the winterize hook up.