What does the drain actually drain?

[moodman]

There are two drain tubes under my Montana HC fifth wheel. I assumed these tubes were just to drain water out of the supply lines and that this is the lowest point in the system. However, someone on this forum told me that these tubes also drain the fresh water tank.
So, is that true? I had always believed that to get the water out of the FW tank you had to pump it out through the 12V system pump. Just looking for a little clarity.
Thanks.

[LHaven]

Usually there are three drain tubes under the rig, the third being the fresh water tank. Look harder, usually in the vicinity of the fill port, where the tank is normally located. Sometimes they get obscured within the corroplast.

[FlyingAroundRV]

You'll probably find there are three drains under the trailer. The two you've found are probably a red and blue pipe with caps on them. There should be a third one with a valve on it. That will be the FW tank drain.

[JRTJH]

There are several configurations used to drain the fresh water tank. Which is used on your trailer is uncertain.

One type is a 1/2" PEX line with either a screw on cap or a 1/4 turn valve which, when removed/opened, will drain the tank.

Another is a lever/valve handle in the convenience center that operates a valve behind the convenience center to drain the tank.

A different type (usually used on tanks greater than 50-60 gallons) is a 1.5" slide valve (similar to the gray water tank dump valves) that has a handle, either at the valve or using a Bowden cable, remotely placed, that when pulled literally "Dumps" the fresh water onto the ground.

Usually, the drain is physically located on the tank, at the lowest part of the tank, so all the water can drain from the tank. Typically, the tank "pick-up hose" that supplies water to the water pump is also located in that "low point collection area" of the tank.

What you'll see on your RV also varies. Sometimes, the low point and water tank drain are visible with the caps/valves a part of what you see. Sometimes the drains are "open tubes" under the trailer and the valves are not visible (such as they are with most convenience centers, where the valves are located above the bottom cover) and sometimes, that 1.5" drain is not associated with the water tank, as no valve, no cap and no visible location that resembles a "water drain".

What's on your trailer may (or may not) look like a "logical way to drain the fresh water tank"....

I'd suggest that any RV owner spend as much time as needed, on their back, on a creeper, under their RV, rolling around, looking at things, inspecting installations, assuring items are properly secured, not loose and not damaged. While under there, pay particular attention to the areas OUTSIDE the frame rails, between the rails and the J-wrap. That's where the body "outriggers" are welded to the chassis rails and where much of the "good stuff" is well hidden by those "scoundrels" at the factory......