Here's a no-brainer if you have visual access to your water tank and you can see the water level through the sides.

Start with it empty and add some convenient amount of water. I have a 25 gallon tank so I added 5 gallons at a time. Mark the level then add some more. A quick pop of the side storage door gives me an idea of whether I have to make a water run while boon docking. Not a biggie.

I travel with only 5 gallons in the water tank and when filling before a trip with the water hose this gives me a guide. (Trivia: Did you know that the Casita 16 is longer behind the axle than the Casita 17'. Makes water behind the axle a bit more of an issue due to the lever arm.)

There are water level sensors but for my needs this was sufficient.

(Trivia: Did you know that the Casita 16 is longer behind the axle than the Casita 17'. Makes water behind the axle a bit more of an issue due to the lever arm.)

Hi Steve, I never knew that but that must be where the extra 100 lbs of tongue weight comes in on the 17'ers

FWIW; Recently, I noticed how the 25 gallon tank virtually blocks the outside storage cubby on the 17 while I have some storage on my 16. At the get together in Brown County recently, I was looking at the other side of the different trailers and I noticed the battery door, the water heater and the shore power door seem to be in the same relationship to each other on both size trailers but that there was more body between the shore power door and the back of the wheel well on the 16 footer.