Can You Drive An RV With 40 Gallons Of Water In The Fresh Water Tank?

by Ken
(Silverdale WA)

Can you drive with 40 gals of freshwater in freshwater tank?

ANSWER: Hi Ken you sure can drive the RV with a full freshwater holding tank, but you should only do that if you are planning on doing some Boondocking (camping in a location that has no water connections, power connections, or sewer services).

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If you are planning on going to an area that has all the connections and services mentioned above there is no need for you to travel with a full freshwater holding tank especially if you are interested in getting the best fuel mileage you can in your RV.

One of the factors that affect fuel mileage in a motorhome or RV tow vehicle is the loaded weight of the motorhome or the trailer you are going to tow. 40 gallons of water adds an additional 334 pounds of weight to your RV. Now that may not sound like a lot of additional weight, but it will affect your fuel economy.

Any effort you can make to reduce the loaded weight of your RV will have an effect on fuel mileage. For example I urge all RVers to always dump their grey and black water holding tanks before hitting the road, regardless if they are full or not to reduce the loaded weight of the RV.

Hope this helps.

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Comments for Can You Drive An RV With 40 Gallons Of Water In The Fresh Water Tank?

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Only if you have to
by: Dan

I don't haul water regardless of where we're going. We like full hook-ups or fill up at the park. If we're going remote, I fill up at the closest place to the site. We have a 3-stage filtration system that we run the water through before it enters the RV, city, or tank.
The lighter, the better.
Happy travels!

Read Your Owners Manual
by: GreenFlyingDragon

I've read a lot of articles on the subject of whether to travel in an RV with or without holding tanks full. In nearly every case the article is focused on operational convenience or fuel efficiency.

I'd suggest owners reacquaint themselves with their owners manuals and, hopefully, their high school physics textbooks.

In the first case, an owners manual will nearly always discuss weight, both maximum limits and distribution, to ensure safe operations and avoid structural failures. Operate within those limits for your safety, and the safety of others. You won't void your warranty, run the risk of a moving violation, have an insurance claim denied or cause premature tire/suspension/brake/frame failire.

In the second case, the laws of physics rule. If you break those laws, there will be consequences. If your manual isn't clear on the subject, write or call the manufacturer for guidance. They'll, understandably, be conservative on this issue. But that's to be expected. After all, they have product liability issues to consider.

Get under your RV and see how your tanks are secured. My truck camper construction reflected it's intended use and CG reality, tanks installed low and supported, indirectly, by my truck bed. It was designed for operation with full tanks and we never had problems doing so when needed.

My travel trailer and 5th wheels were more of a mixed bag, but the manufacturers guidance was, generally, to avoid travel with tanks full or partially full. They don't care about your fuel mileage, but are concerned about liability.

Looking at how my tanks were supported, some were held up by just two steps, others were sitting on the frame rails and further supported by straps. These techniques are likely adequate for the weight of a static load, but the forces associated with potholes, bridge transitions, etc may be just too much.

So, my suggestion is to read and comply with your manufacturers guidance, and always minimize your RV weight as much as possible while traveling. All of your wear components will thank you, you'll use a bit less fuel, enhance safe operation, and even reduce driver fatigue a bit.

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