Howdy Folks,

I'm wanting to sanitize the fresh water tank on my 2007 TowLite 1907T Anniversary Edition Hi-Lo, so I need to know the tank volume for adding a correct amount of bleach (1/4 cup/15 gal). I have the Hi-Lo brochure that quotes 30 gal. But, being a retired scientist I then tried 2 empirical volume measurements. I first measured the tank dimensions at 7" x 28" x 45", which gives 8,820 cu in, and calculates to ~38 gallons. I then filled the tank to overflowing, then drained it into 5 gal buckets and got 4 buckets, or 20 gallons. In conclusion, I'm losing my mind with 3 different volumes. Can anyone tell me what I did wrong, or to a reputable water tank psychiatrist?

Lou, I've always just assumed the tank itself is 30 gals, but the hot water tank holds 6 gals, so the total is 36. Still, I've simply used 1/2 cup of bleach in mine to sanitize it. However, DO fill your tank partway before you add any bleach, because the hot water tank gets filled first and if you put the bleach in first, it all does into the hot water tank.

Then, I just let everything sit for several hours or overnight, and then drain the tanks by running both hot and cold water through the inside faucets, which disinfects the lines too. Finally, I repeat the whole process by filling the tanks with fresh water and draining them through the faucets too (into the grey water tank of course). I empty the grey tank on a nearby tree. Bleach doesn't hurt vegetation.

BTW, the fresh water drain does not drain the hot water tank. I can't explain why you were only able to drain 20 gals. I use 5 gal water jugs to fill the tank(s) when camping and 4 of those does not fill the trailer's tank.

- Jack

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Hi-Lo 1707T - Tire Minder TPMS on Tow Vehicle and Trailer, 300W Solar Battery Charger, Equal-i-zer WDH, Progressive Dynamics Converter, Fan-Tastic Fan, LiFePO4 battery 12V DC Electrical System, SoftStartRV mounted on A/C
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Lou, I was under my trailer today, doing some maintenance and I looked at the water tanks. Similar to you, I'm a retired engineer, so I resonated to your questioning the capacity after measuring the tank and then measuring the volume when you emptied it.

I know you realize the tank is not a rectangular SOLID, but is more like a rectangular "blimp". It expands quite a bit due to the pressure of the contents when filled. And, if you drain the fresh water tank using the curbside drain, it's quite possible you don't get all the water out of that tank, depending on how the drain line is routed.

I bet, if you start with an empty tank and measure the water volume as you FILL it, you'll find it holds around 30 gals, plus 6 more for the hot water tank.

- Jack

Thanks much for your advice and thoughts. I've continued experimenting, and can not find 36 gallons of water after filling the tank and water heater. This time I jacked the trailer so it was "perfectly" level (using 6 ft level on frame in 2 directions). I then filled the tank to overflowing (from the overflow port adjacent the filling port). The tank outlet and drain are on the "passenger side" of the trailer, so to completely empty it, I tilted the trailer toward the drain by rolling the "driver side" wheel onto a 6" ramp. I detached the clear Tygon tube from the plastic drain valve and collected water in 5 ga buckets. Result: ~25 gallons. I then tilted the trailer in the other direction and drained the water heater into a 5 gallon bucket. Result: ~5 gallons. Total: 30 Gallons.

Well, you're closer! lol. I have no other ideas on this. I've never totally filled my tank with water from my water jugs, so I can't really say what my tanks hold. I just know that putting 20 gals in (when the tank is close to empty) does not fill it.

- Jack