2nd Fresh Water Tank - Fiberglass RV

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Old 01-26-2010, 11:24 AM   #1
Trailer: Scamp 16 ft
Posts: 34
I have a 16ft Scamp and recently installed an outside shower. We love it except for now we use a lot more water. I want to install a 2nd fresh water tank under the rear bench (driver side). Has anyone done this? If so how did you connect everything and what size tank did you install. I would like to install at least a 20 gal (don't have to worry too much about the size of the gray water since most of the water is used on the outside shower. Just want to be able to take long hot showers.


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Old 01-26-2010, 05:26 PM   #2
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You might want to read about how peterh added a bigger fresh water tank under his modified U-shaped dinette.

Link Here

Frederick - The Scaleman
1978 Fiber Stream 16 named "Eggstasy" & 1971 Compact Jr. named "Boomerang"
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Old 01-27-2010, 05:12 PM   #3
Trailer: Scamp 16 ft
Posts: 34
Thanks for that link, I have seen that but I am looking for something a little different. I want to keep the existing tank and add a 2nd one. We do not use the storage under the rear dinette bench and so we were thinking of putting the tank there. Any ideas on how to connect them together. I have some but I was wondering if anyone else had any thoughts.

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Old 01-27-2010, 05:58 PM   #4
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without seeing your trailer i would think to put in a "Y" connection somewhere before the pump and put a manual gate valve (shutoff valve) on each line from the tanks somewhere convenient to reach so that you can use either tank or both if you wanted.
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Old 01-27-2010, 06:25 PM   #5
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Trailer: 2002 19 ft Scamp 19 ft 5th Wheel
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20 gallons at a pint a pound adds a considerable amount of weight so B careful you don't get your rig out of balance. 8LB X 20 = 160LB.

If you have a pickup, you may be able to carry it in the bed of the truck and use a 12VDC on demand pump and garden hose (White) to supply it directly to the city water entrance of the camper.

Use a demand pump like the one in the camper, it would keep your system pressurized up to the time it goes dry. Your on board demand pump / check valve would keep it from flowing back to your on board tank. When the aux tank goes dry then switch to your on board pump and continue on.
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Old 01-27-2010, 08:32 PM   #6
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Trailer: 1983 13 ft Scamp
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Also, to get the capacity of the tank ya want to put in, cube it in inches and divide by 231, that will give you the gallons. Larry
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Old 01-29-2010, 04:04 PM   #7
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Trailer: 2005 19 ft Scamp 19 ft 5th Wheel
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20 gallons at a pint a pound adds a considerable amount of weight so B careful you don't get your rig out of balance. 8LB X 20 = 160LB.
I thought I'd posted this earlier, but, yes, weight is an issue when you add water capacity. I'm the guy who remodeled his Scamp to have a rear bench seat with a 20 gallon water tank underneath, and it's good to point out that my Scamp is a 5th wheel trailer with a hitch weight of seven-hundred pounds, give or take another hundred.

It's pretty normal for 5th wheels to have 25% of the trailer weight sitting on the hitch, and that gives 5th wheel owners a lot of latitude in how they load and distribute the weight of their trailer.

That's not true with conventional-hitch trailers. Conventional hitch trailers should put 10 to 15 percent of their trailer weight on the hitch; that's 200-300 pounds for a 2000 pound trailer. Throw 20 gallons of water in the back of your trailer and you'll substantially reduce the tongue weight, which can cause unsafe sway at freeway speeds.

If you gotta have more water and you're not a 5th wheel owner, consider carrying a few jerry cans in the back of your vehicle. That way you won't unbalance your tow, and you won't have to move your trailer when you need to refill the tanks. If you're not comfortable lifting a full jerry can, consider getting a transfer pump; I've seen transfer pumps that can move a gallon of water in three or four (energetic) strokes.

It's also worth noting that, because some of the tank's capacity is "dead space" (the output and overflow/fill fittings are not right at the bottom and top of the tank) Scamp's "10 gallon" tank holds something closer to 8-1/2 usable gallons. Three 3-gallon jerry cans will double your water capacity.

One last "capacity" comment before I go. Fresh water capacity is one thing, grey and black water capacity is another. Our Scamp 5er has a 27 gallon grey waste tank, and our "20 gallon" capacity fresh tank holds 17 usable gallons of water. Some of the fresh water does go down the toilet and into the black tank, but, even so, if we fully topped our empty fresh water tank when it ran dry we would overflow our gray water tank before it ran dry a second time. We can only "top up" the fresh tank once before that happens, and even then we can't completely refill the tank.
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Old 02-05-2010, 12:07 AM   #8
Trailer: Scamp 16 ft
Posts: 34
Thanks for some of the input, the weight is really a non issue because I do not travel with more then a couple of gallons in the tank(s) until I get to where I want to stay. The grey water is not an issue either due to the fact the main reason I am adding a second tank is to feed my outdoor shower.

Just wondering if anyone has done this before and if so how they did it.

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