As a concept it is a neat idea but I have to question the validity of practical use.

The weight of the hose and water will severely limit the effective height. Not to mention the thrust required to counter the reaction forces from the nozzle.

Then you get into the practicality of flight time and manpower. The pilot and hose tender could team up and be on a ladder with a much bigger hose in the same time it takes to set up the drones.