Plumbing installation in my van

[Yuseph]

Hey,

I'm located in Paris. forgive my average foreign English.
I'm about to install all the plumbing in my van. I'm new to this. I'm wondering if I should recapture the used water from the sink and the bathroom and reinject it into the flush tank or do nothing and waste that water.
Also, since I wont be getting water supply from the city I dont really know if the absence of pressure will be a problem. Has the storage water heater pressure on the output ou shall I connect a water pump there ? shall I add a water pump on the input too ? The water tank might be placed on the roof so therell be a natural flow downward due to gravity. Now say I decide not to recapture the used water from the sink and the shower what's the point of having a grey water tank cant I just redirect all used water to the black water tank along with the used water from the toilet ? It may cause me to drain the filthy tank more frequently but still
What about the toilet ? Will there be water stagnating in the bottom on that bowl or it stays just dry ??
I told you i didnt know much

 

[ShaunCorbs]

You can do but you have to make sure that water is clean and no particulate/ bits in it eg food stuff etc

And there will be water in the toilet as it creates a trap to stop any smells etc (from a normal drainage system )