Under tray water tanks?

[Chris88]

I'm a plumber by trade I just used some left over 6" pipe to caps the width of my tray it's mounted under the rear if you are going to make one your self I aded 2 taps one at the bottom of the cap one passenger said and one at the top of the cab driver side idea is you have air flow in from one more flow of water out of your lower tap still toying with the idea of connecting my my compressor to it to build up water pressure