Freshwater Supply - Can I use the drain?

[Kntcor]

Hello all!

We are setting up our RV for full timing in a “permanent” spot for the next year or so.
We are planning to add skirting around the base for some extra insulating factor and would love to have our freshwater supply inside that more insulated area. Can the freshwater be safely supplied from the fresh water drain under the RV?
Any thoughts on this would be much appreciated! We have a 2012 Keystone Outback Super-Lite 298RE.

[NH_Bulldog]

Short answer is “no”. Long answer is “oh heck no”.

That being said, the freshwater tank is not a pressure vessel. You fill it, turn off hose, run your inside pump to supply water to your fixtures, when tank is empty repeat.

You could conceivably re-plumb the city water connection so that it is under the camper, but that presents a whole other set of issues.

[dutchmensport]

I'm a bit confused over what you are wanting to do. Are you asking if you can hook up the garden hose to a connection under your kitchen sink, instead of the connection on the side of the trailer or in the convenience center of your trailer? If this is right:

The plumbing in your camper is just that.... it's just some basic plumbing. And, probably, theoretically, you could attach a connection point on the cold water line under the kitchen sink and attach a garden hose there. I do not think it would work, and here's why:

The flow of water in the camper is designed to flow one direction. Connecting under your sink would require the cold water to flow backwards from the sink, and then connect to the junction where the main cold line comes into the camper and also where the hot water line is. From that point it would flow forward through the hot water lines in a forward direction.

However, the pressure of the cold water, right at the faucet might cause the cold water to back feed, or attempt to backfeed back into the hot water line, right at the faucet. If that happens, you'll never get hot water at the sink as the water pressure from the garden hose is attempting to fill the hot water line from both ends.

Except for the kitchen sink, I think it would work OK everywhere else, as long as the kitchen sink was not turned on.

If you are skirting the trailer and you have a water connection on the outside of your camper, it makes better sense to get access under the trailer, remove the underbelly material, and splice the "in" line. One thing you'll need to do is install a check valve, or a cut off valve so if you camp conventionally, and you attach a garden hose to the outside of the trailer again, water will not just spew out your new connection point.

[Kntcor]

These answers are super helpful!
We were hoping to fill our freshwater tank from the freshwater tank drain. We thought that since it would be filling the tank that pressure wouldn’t be an issue but it sounds like it’s just not a good idea. Thank you!

[chuckster57]

Originally Posted by Kntcor

These answers are super helpful!
We were hoping to fill our freshwater tank from the freshwater tank drain. We thought that since it would be filling the tank that pressure wouldn’t be an issue but it sounds like it’s just not a good idea. Thank you!

you could fill the fresh tank that way, but its not really an efficient way. The drain is 1/2" at best and you'll have to overcome the pressure of the water pushing down as it fills.

[dutchmensport]

OK, let me back-up a moment. I think I miss-read the original post. Chuckster got my attention.

You are wanting to connect the garden hose to the fresh water TANK drain. You'll need to attach a garden hose spigot to the drain line sticking out BELOW the trailer, right?

Yes, I think you can do that. Based on what you are wanting to do, it sounds like you have a gravity fill port on the side of your camper to fill the fresh water tank? Right?

Connecting to the tank DRAIN would work, provided the air vent for the tank would allow adequate ventilation and not cause a vacuum. If water fills too fast, pressure in the tank could build and it potentially could cause it to burst.

Attaching a connection to the drain pipe will not hurt anything. Make sure you install a cut-off valve too. You will not want to leave that valve open as water will constantly be wanting to drain out that hole. Once the tank is filled, you'll absolutely have to turn the garden hose spigot off and most likely, turn the new valve off also so the tank won't drain.

The biggest concern would be your tank causing a vacuum because the water would fill too fast. With a gravity fill port, air escapes through the overflow vent. Also, air escapes back up through the fill port too. That's why you can turn the water spigot on full and the tank will fill ok. However, if it fills too fast, the fill port will burp backwards because the water created a vacuum and it's spewing water out as fast as it's going in. You have to slow the water down. (I had a gravity fill travel trailer in my past that was really bad at doing this).

Pumping water via your on-board water pump then will be no issue as water is flowing in the correct direction starting from your fresh water tank.

You can add the connection and test it. If it doesn't work or causes problems, you can always use the cut off valve for easy draining your fresh water tank. Nothing lost there. .... just ... fill the tank slow so it doesn't cause a vacuum and be under pressure.

[chuckster57]

If your ADDING liquid aren’t you creating pressure not vacuum?