Firfighting equipment...
Self contained HALE floating gas (two stroke!) fire pump...180 gpm at 45' head. Hook up your hose, set this in a swimming pool, pull the cord to start and get ready!
You can also grab empty KIDDE fire extinguishers for next to nothing. Rinse them out well, fill to about 50% with water. Using a rubber tipped blow gun, pressurise to your liking! A Quincy two stage compressor running at 400+ PSI works very well. Be warned though! 400PSI water stream at 1 gallon per SECOND kicks like a 12 gauge 3" magnum and then some!
-DAK-