Nice job. It looks like it came from the factory that way. In fact, it's almost impossible to see that it used to be a fire truck!!!!
I used to drive a water truck, actually a few different types, and the poney motor for the pump was allot better then a PTO for spraying while driving. If I was just using hte hose and parked, it didn't matter, bur for dusting the roads, the PTO pumps were a real pain to get engine speed and water presure just right.
How many gallons will the water tank be? The small 1,000 gallon tanks were great for small areas, but ran out of water way too fast. 3,000 gallons was the norm and a good comprimise on being able to drive the truck and have enough to be useful. Five thousand gallons was just too much weight when full for the trucks that I drove. Steering, stopping and getting stuck were constant headaches. Many times I would try to turn and the front tires would just keep sliding along straing until I could stop. One time I was on a hill and the front tires came off the ground on me. I sat there draining the tank until the front tires came back down. I guess it was about a thousand gallons that I had to dump.
Eddie