TOWCHECK FIELD GUIDE
How RV water changes payload
Water adds roughly 8.34 lb per US gallon, so tank strategy can materially affect a lightly rated trailer or motorhome. The location of each tank also changes which axle or hitch carries the added load.
What the terms mean
Tank capacity is volume; payload is weight. Fresh, gray and black contents all count toward the vehicle’s loaded weight, even though waste density can differ from clean water.
Worked example
Common mistakes
- Counting fresh water but ignoring waste tanks
- Assuming tank weight is centered over the axles
- Treating capacity as the amount actually carried
Frequently asked questions
Should I always travel empty?
TowCheck does not prescribe a strategy. Compare the planned condition with ratings and operational needs.
Is one litre exactly one kilogram?
It is a practical water approximation; temperature and tank contents vary.
Where do I add water in TowCheck?
Use the trailer payload or water-weight calculator, then confirm the resulting loaded configuration.
Primary references
These sources support terminology and general planning context. Use the current documentation for your exact vehicle, trailer and components.
Continue with your own numbers
Run the Complete Tow Check, use the scale worksheet, or review the calculation methodology.