Water Tank Size?

Are you taking showers flushing toilets or just washing a few dishes? Will it be just you or a spouse and twenty kids? All of that comes into the proper answer. In our truck campers we only used the tank for washing dishes and hands a five gallon tank lasted several days. In our trailer that had a shower and a flush toilet I don't think they made a big enough tank.

I've pondered this question, too. My husband thought I should put the tank back in its original spot but I have other plans for that storage space. I'm planning on possibly using my Reliance 5 gallon fresh water container, either in the closet or under the sink, preferably under the sink. I can always carry extra water in my tow vehicle and store drinking water in the icebox or stove (yes, I said stove, that's a lot of space, too.)

Jennifer, you can never have too many shoes.

To jude how much room a 15 gallon tank will take, think of 15 empty gallon jugs sitting side by side. It's not all that different from your original tank. If you're VERY careful, 15 gallons will work for a weekend of dishes and faces, I think you'd be pushing it if everyone used the toilet three times. Depends on the toilet.

   Water tanks are nice.. The first lady of the tribe always has me put a least 5 or 6 gallons upon arrival where ever we might be if we don’t have a hook up. (I think our tank is a 16 gallon one, and we do not have a toilet or shower)
   I do not travel with water in our tank. If I was to boon dock I'd carry my 5 gallon jerry can full of water and use it to carry more in.. I have a “rain-catcher” from the sailing days too.. I guess I could use that to boon dock with as well.
I don't have a power electric pump. I don't really miss that, but if I ever have to rebuild the counter top I'll put in a foot pump, they really free up the hands.  
   The sink is so shallow in the Loflyte.  I chuckle a little bit but my wife will wash dishes in the thing.  I prefer filling up a dish pan and clean’em up outside, weather permiting of course

Another very important thing to remember about a water tank is how it will effect the balance of your trailer. We think of water in terms of not much weight when drinking a glass full, but when hauling 15 or 20 gallons of fresh water and 20 or 30 gallons of black water you can be adding 300 or 400 pounds of weight if the tanks are in the rear that could take all the weight off of the hitch causing a severe sway problem or if added to the front it could cause an excess amount of tongue weight causing a hitch failure or damage to the tow vehicle. Also this weight can cause a suspension over load on one side of the trailer if it isn't designed for it. On some trailers you will find a heavier duty spring on one side to allow it to safely carry more weight on that side. another thing to consider when redesigning and adding tanks is the load rating of your tires, wheels, and bearings.
We sometimes forget how much weight we add to a dry or empty trailer when tanks are filled, cupboards are loaded, and the center aisle piled full of all the things we need to take with us. I suggest that people load their trailer completely full of every thing they are going to haul in it including firewood, cement blocks, tents, awnings, outboard motors, and anything else they will want to haul.Then take it to a scale and weigh it, just the trailer, unhook and move vehicle off the scale.Then back the trailer wheels off the scale, unhitch the tow vehicle leaving the jack sitting on the scale to check tongue weight. Next do the math and make sure that 10% or more of the total weight is on the tongue and that your hitch rating exceeds that amount. I personally like at least a 30 or 40 percent safety margin on my hitch.
I know this sounds like a wasted effort but there are two things I don't want to be responsible for, Myself or somebody else being killed or seriously injured. I am of the opinion that would spoil a good vacation.

I wondered about the weight distribution with the tank on one side and how it was compensated. That was one of my concerns and reasons for not replacing mine. I've dealt with the weight and balance issue before. That's also one of the reasons I refrained from filling my tanks this past summer. Water is a lot of extra weight.