From a design prospective I would first wonder how heavy the water would be to push around. Otherwise I think such an idea could have potential in a real world market, although there might be a few details I would change. I would like to hear more about it before I give any more detailed comments.
The drawing itself looks like it took a long time to do and is very interesting to study. Design is time consuming but well worth it.
Heh, I remember designing vacuums when I was a kid...amusingly, like cars, I could only design ones that looked like they were from the 1970s for some reason =p
There is already a water filter Vacuum called a Neptune but an upright version seems very neat. I like the hose too it reminds me of a Lux Velocity and your anti-tip design is a really cool idea. I would deffo buy one of these. Very well done!