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

Veebyes
Explorer II
Dec 23, 2016
I guess running out of water is no fun at all. A high water capacity was on our 'must have' list & we scratched anything under 80gal off the possible purchase list.

As a previous poster noted you will have to open up the bottom, have a look & take some measurements. Chances are you will have room to install something much larger.

We have 100gal total & it is reassuring when we do not have water at the site knowing that we are good for 6 days easy.

Nothing wrong with the bladder in the truck & pump method if a little inconvenient.
FLY_4_FUN
Explorer
Dec 23, 2016
For the work and expense involved in plumbing in a new larger tank, I would just get a semi-custom water tank for the truck. I got a 33 gal tank and 12v transfer pump/fittings for $200 and can remove it for all but the required trips. I actually don't need the pump with my current rig as I can select winterize and it sucks the water out of the tank into the rv. Its a nice option if you have the space in your bed.

Daryll
laknox
Nomad
Dec 23, 2016
korbe wrote:
I had to fix the FW tank supports once and while down there, I was able to see how the tank was supported and how it could be modified - or enlarged. Mine could be increased by width and length, but not the thickness. And then I would need to see what dimensioned tanks are out there.

When talking cubic, it only takes a few inches to gain quite a bit of capacity.

Lyle
korbe
Explorer
Dec 23, 2016
I had to fix the FW tank supports once and while down there, I was able to see how the tank was supported and how it could be modified - or enlarged. Mine could be increased by width and length, but not the thickness. And then I would need to see what dimensioned tanks are out there.
laknox
Nomad
Dec 23, 2016
mhardin wrote:
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.

I've seen guys put a small bladder tank on their roof, ~20-25 gal, with a simple gravity feed. Also seen guys with a larger bladder tank in their truck bed with a transfer pump. Personally, I carry 2 7 gal "blue cubes" with me to our long weekend boondocker. One I'll use for hand-washing and tooth brushing outside; the other is a "spare". I've dumped both in my fresh tank on one occasion. Most times I'll dump whatever's left in both of them in the black tank for the drive out and to the dump site, about 30 miles away. If anything is left after that, it goes to help put out the camp fire.

Lyle
mhardin
Explorer
Dec 23, 2016
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.
Nunyadamn
Explorer
Dec 23, 2016
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.
Allworth
Explorer II
Dec 23, 2016
Icon-Direct (Google them) may have other tank sizes available that will fit your space.
agesilaus
Explorer III
Dec 23, 2016
No use even speculating until you get under the fiver and drop the coroplast so you can see where there is room.
4Kellys
Explorer
Dec 23, 2016
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!

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Possible to install larger fresh water tank?

30 Replies

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