My 5er has an advertised fresh water capacity of 54 gallons. In doing a water test this past summer, in reality it only holds ~ 36 gallons. I called Forest River and they claimed it's actually a 40 gallon tank that truly can't hold 40 gallons, the remaining water capacity is found in the 12 gallon water heater and the capacity contained within the plumbing throughout the trailer. I called BS to the FR rep, and he agreed...That still doesn't do me much good as far as fresh water capacity. We don't dry camp much, but most parks we frequent have only electric at the sites.Here's my question: is it possible to remove the existing 40 gallon fresh water tank, and replace with something larger? I haven't looked at the physical constraints yet (underbelly), but I have plenty of CCC in the 5er for additional water, and would structurally support it as required. I've seen up to 96 gallon fresh water tanks - again, not sure if it would even fit yet.I searched the forum to see if this topic has been addressed before, and did not come up with anything.Has anyone swapped out their fresh water tank for a larger one? Thanks!

If you don't dry camp much I can't see why you would go to that expense, time and effort. It would certainly void your warranty, making structural changes like that. I don't know where you camp but we've never seen a campground that didn't have at least water. A lot of them don't have sewer for sure but almost all we've ever been to have water, or water and electric. FR would have many reasons to deny a warranty claim if you modified a brand new fifth wheel in my opinion. I would think about that aspect first. Good luck and Happy Holidays to you!

No use even speculating until you get under the fiver and drop the coroplast so you can see where there is room.

Icon-Direct (Google them) may have other tank sizes available that will fit your space.

What size grey and black tanks do you have. You will have to verify you can hold that water somewhere. I have a 86 gallon fresh but only 35 gallon black and grey tanks. Usually we fill the grey tank really fast and have a bunch of fresh water left. For your trailer, I think it is possible, anything is possible. You will have to see what can fit for your specific setup. If you have the room, replacing the one tank with a larger tank would be easier, but if you can't fit that one, you could use two tanks and run a line between the two - water will find a level so it will make both tanks equalize. That should feed water to the tank with the pump outlet. It's a pain, but if you really need more fresh water you could get some of those large 5gallon fresh water jugs from camping world and fill your fresh water tank. To make it easier, get a fresh water pump and pump from the external jug to the fresh water tank on your trailer.

Even if you don't have room for a larger tank, you may have room for a second tank somewhere. Or, you could put a tank in the bed of the truck and use a transfer pump to move it to your main tank.

Possible to install larger fresh water tank? | Good Sam Community

30 Replies

Stefonius
Explorer
Jan 04, 2017
I bought a blue food-safe 55 gallon plastic drum for $10. It travels with me when we boondock, and my on-board water pump will refill the tank from it when set to the "winterize" position. Very useful when camping at a festival.
slomark
Explorer
Jan 03, 2017
After pulling down the coroplast I noticed that the trusses were spaced approximately four feet apart between the I-beams. And several of those bays, the space between adjacent trusses, were not being utilized. I added another fresh water tank of 42 gallons, and tied it into the existing plumbing, while adding a separate fill and vent line. It works fine.
24v
Explorer
Jan 02, 2017
kep5niner wrote:

^^^^ That is the concept I have in mind, or at least replacing the tank in my underbelly. Thank you for posting that information.

It is my low budget version. :)
kep5niner
Explorer
Jan 02, 2017
^^^^ That is the concept I have in mind, or at least replacing the tank in my underbelly. Thank you for posting that information.
24v
Explorer
Jan 02, 2017
Here are a few quick pictures of the larger tank install. I know it isn't the most economical solution, but I don't want to have to pack any extra containers and have to deal with filling it up when low. This way I can fill it before I leave my house, and not worry.

Original 20 gallon tank under the bed, next to the flip up storage.

New 50 gallon tank vs old 20 gallon tank.

New tank in place, barely fits.

BTW, for those saying this is too much of a pain in the ass, if I was not doing the grey water recycle system I would have literally had to buy this tank, and a few fittings from Home Depot as the fill is a different type of fitting. So I had to remove a divider, pull the old tank, buy a new fitting for the fill, and put it back in. Not a pita at all. Obviously this will very by trailer, just my experience.
Moderator edit to re-size pictures to forum recommended limit of 640px maximum width.
ol_Bombero-JC
Explorer
Dec 28, 2016
kep5niner wrote:

I searched the forum to see if this topic has been addressed before, and did not come up with anything.

Has anyone swapped out their fresh water tank for a larger one? Thanks!

Addressed before:
You prob didn't find any threads for that mod, as it's too much of a PITA. Owners reach this conclusion.......
Easier to add capacity via portable tank/s -or- a second tank mounted "somewhere" and pump from aux to main tank.

Regarding "search" - did you also check the archives? Standard search is for one year (only).

BTW - always "made do" with what I had, and as many have already said,
- unless boondocking (dry) - never been in a campground without access to water....either at the site, or somewhere in the campground.

Years ago with TTs camping in state parks, nat'l forest, etc. I carried 3 fifty foot sections of cheapie hose and a water thief.
Connect, fill, disconnect - during "quiet" times.

Good luck with your plans and/or water conservation!

:)
lee_worsdell
Explorer
Dec 28, 2016
I had same issue on my last trailer. So I went and bought a 25gallon fresh water drum. Stands in the back of the truck perfect. I just bought a small pump and when I was low just filled from the truck. works great and also bought a valve that I can open both grey waters and they fill together. Then close the valve and drain black followed by the grey. I cpould go all weekend at a track or event with out fillinf from tanker
Wild_Card
Explorer
Dec 27, 2016
Look into some poly or polyethylene tanks for the back of your truck.
shadows4
Nomad
Dec 27, 2016
After pricing some of these tanks, I'll just buy another 7 gallon jug to go with the one I already have and call it good. Man they are expensive.
Twain
Explorer
Dec 27, 2016
There was someone on here who added an aux water tank to a passport TT. They ran lines into the original tank. I think he put it under a bunk bed.