Water tank size & placement

[ReluctantTraveler]

After literal years of planning and thinking about building out a flatbed truck camper (and then postponing the whole project for financial/work reasons), I'm finally nearing a place where I can make it a reality.

One of the details I'm still trying to work through is the size (and more importantly, placement) of the fresh and gray tanks.

Based on my current experience traveling in our tiny travel trailer, I'd like to have at least 60 gallons of fresh water (and ideally closer to 90). The two questions I'm working through in my head...

1. Size. I notice most RVs have a 1:1 fresh:gray capacity ratio, while most expedition vehicles have a 2:1 fresh:gray capacity ratio (eg 60 fresh and 30 gray). I'm not sure I understand why they wouldn't be equal, since many places don't let you dump gray water on the ground.
2. Placement. I've attached a very rough sketch of my floorplan below. I planned to place the fresh water tank along the front wall up near the cab, next to the bathroom and entry door (inside a step into the cabover). I'm not sure where I would fit the gray water tank at all.
   
   I could fit a 4" basement on a standard height box, or go with a slightly higher box (total rig height of 11' 3") and fit in an 8" basement or so, if that frees up more options.

Here's my floor plan at the moment...



For those who haven't been following along, quick summary...

• F-550/Ram 5500 platform crew cab with 84" CA and 11-12' flatbed
• Total Composites or Cascadia Composites cabover box
• 11' box with 2' departure angle (the max size multiple vendors have told me they'd put a removable box on a flatbed)
• Trying to comfortably travel for a 1-3 months at a time with a family of 4 plus dog

 

[ReluctantTraveler]

I'd suggest permanent mount on the chassis - I know, I know, you'll have your reasons not to ... but that's my .02

Then you could more easily integrate space under the truck for water tanks (either between or outside the frame rails). And not have to pull a rabbit out of your behind every time you are loading/unloading the box.

I don't understand the rabbit reference, but chassis mounted isn't gonna happen. I know there are lots of good reasons to do it, but I want the option to decouple them (more easily than a chassis mount allows).

As for the other tread re: reducing emissions and fuel consumption ... good grief ! (F550 !)

Fair, but after seeing other people's reported numbers, it doesn't seem like the fuel economy is particularly better with smaller trucks or even vans once you start loading that many people and their stuff into the rig.

Tradeoffs and all that.

 

[rruff]

For those who haven't been following along, quick summary...

• F-550/Ram 5500 platform crew cab with 84" CA and 11-12' flatbed
• Total Composites or Cascadia Composites cabover box
• 11' box with 2' departure angle (the max size multiple vendors have told me they'd put a removable box on a flatbed)
• Trying to comfortably travel for a 1-3 months at a time with a family of 4 plus dog

How much camping experience does your family have and how much do they like it? How old are the kids?

 

[ReluctantTraveler]

How much camping experience does your family have and how much do they like it? How old are the kids?

We have logged 12k miles in our 16' travel trailer. We're not into "camping," and we don't really offroad. We do enjoy vehicle-based travel and prefer NOT to stay in hotels. We tend to stay for 2-3 days at once place and move on. Longest trip has been 6 weeks on the road. Kids are elementary aged.

Heading off some potential questions:

• We have a camper now. It works, but it's small, 3-season only, and towing sucks.
• Commercial class C RVs do not have 4 crash tested belted seats. Host used to make a crew cab model, but the used ones are still ~$100k and quite dated.
• Yes, we do often stay at campgrounds with hookups. No, we don't always do that, and with our family of 4, water VERY QUICKLY becomes an issue. In particular, state parks often have fresh hookup but no sewer.
• I've been down the path of other options many, many times, and am not interested in discussions around alternatives at this time.

 

[ReluctantTraveler]

Another option, carry fresh and grey water in multiple, smaller containers and store outside of camper. Eg. in truck cab, in under deck storage boxes, on rear bumper etc.

Some folks carry drinking water seperately. Say, in a carboy or cube or store bought bottles. These can be stored in various places.

Grey water could be similar. Maybe a small tank under the shower that could be swapped out, or emptied. Likewise under the galley sink.

Perhaps emptied in a washroom.

Or a transfer pump might be used to move the liquid to another container stored elsewhere.

Question, have you been given a price estimate that you would share for an assembled composite camper (with windows, vent and entry door) in the size mentioned ?

Or have a budget for this part?

Just curious, as I think others like the idea for themselves.

I'm still getting final numbers from folks, but...

• The size box I want (11' floor + 2' departure + king-size cabover, 8' wide) is about $32-35k assembled with an Arctic Tern door, mounting points, and manual jacks.
• Adding windows and electric jacks drives the price up, of course. I'm still getting quotes back on that.
• The low end of "we build out the inside for you" was around $110k, which is reasonable once you account for parts + labor, but more than I want to spend.
• I've budgeted around $50k for the truck, and hope to have enough left over to add a LiquidSpring or Kelderman setup for more comfy driving without the camper on, plus easier campsite leveling.

I'm still pricing out the components for a DIY buildout of the box, and will be happy to share once I have them. I'm currently leaning towards IKEA for the cabinets (affordable and easy to assemble/install).

I've done electrical and plumbing in campers before (including a big lithium battery upgrade), so that part scares me a lot less than the carpentry aspect.

 

[ReluctantTraveler]

That sounds a good deal. Hope pending tariffs don't affect that too much for you.

It seems on par with what a scaled up version of the stock TotalComposites boxes would be.

Cascadia Composites manufactures here, so they might be a bit less affected, but Arctic Tern stuff might be hit by those stupid tariffs.

 

[Ozarker]

Consider adopting these;

 

[ReluctantTraveler]

Consider adopting these;

As in tuck the bladders into weird spaces where a hard tank wouldn’t fit?

 

[Ozarker]

As in tuck the bladders into weird spaces where a hard tank wouldn’t fit?

Lots of advantages with a portable bag, and yes, you could build your weird spaces to fit the bag or the bag could fit in smaller places and not be as full.
Bags weigh less, very durable especially inside. Conform to odd spaces if needed, easy to clean too. Cheap too!

Probably not good for black water.....poooo!

 

[ReluctantTraveler]

Lots of advantages with a portable bag, and yes, you could build your weird spaces to fit the bag or the bag could fit in smaller places and not be as full.
Bags weigh less, very durable especially inside. Conform to odd spaces if needed, easy to clean too. Cheap too!

Probably not good for black water.....poooo!

I seem to recall an earthcruiser walk-through video where @lanceatm mentioned using one of those for additional water storage in an odd place. Thanks for the suggestion!

 

[Joe917]

What is the toilet? Composting highly recommended. No water needed!

 

[ReluctantTraveler]

What is the toilet? Composting highly recommended. No water needed!

Probably urine diverting. Had originally been thinking cassette (have one now), but the Separette mini is very appealing.

 

[jkam]

I have a 60 gallon water tank in my 24' Lazy Daze on a Ford E series chassis.
It is under the couch on the right side. About right in the middle of the coach.
To offset that weight, they put the generator , propane tank and batteries on the opposite side.
Pretty well balances out things.
My gray tank is 32 gallons and it is under the rear near the axle.
My black tank is 28 gallons and is next to the gray tank.

I travel with a buddy and we boondock in places for weeks at a time.
He uses a lot of water and we bought a 150 gallon water bladder that fits perfectly in the back of his jeep Grand Cherokee.
We take that to town when needed and bring water back to the RV's. It has worked out well for us and saves having to move the RV so often. And it rolls up into a small bundle when not needed.

 

[ReluctantTraveler]

I have a 60 gallon water tank in my 24' Lazy Daze on a Ford E series chassis.
It is under the couch on the right side. About right in the middle of the coach.
To offset that weight, they put the generator , propane tank and batteries on the opposite side.
Pretty well balances out things.
My gray tank is 32 gallons and it is under the rear near the axle.
My black tank is 28 gallons and is next to the gray tank.

I travel with a buddy and we boondock in places for weeks at a time.
He uses a lot of water and we bought a 150 gallon water bladder that fits perfectly in the back of his jeep Grand Cherokee.
We take that to town when needed and bring water back to the RV's. It has worked out well for us and saves having to move the RV so often. And it rolls up into a small bundle when not needed.
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Wow, those bladders are a LOT smaller than I'd have expected for how much water they hold!

 

[mog]

He uses a lot of water and we bought a 150 gallon water bladder that fits perfectly in the back of his jeep Grand Cherokee.

A +1 for bladders. A great way to haul 'extra' for rare times you might need a much greater supply. I bought a bunch of 50 gallon military surplus Mylar bladders awhile ago, and they fold into abut a 12"x9"x2" package. At $5 a pop, also pretty much disposable if need be.



Heck, being Mylar they might be a good way to make your Expo rig a temporary moonshine runner when your 55 Dodge Coronet is in the Sheriff's impound