They normally get sold with the anti-siphon with the kit. Make sure that you use it, otherwise, although a long-shot, you could really contaminate a water system badly.
Also, don't forget the winterize that line when you put your unit away for the winter. The water in the hose and sprayer will freeze and damage it. I just blow it out with compressed air.
2014 RAM 2500 Laramie 4x4 Quad Cab w/Cummins Turbo Diesel, 2009 Rockwood 2607, and 3 'yaks!
300W of Suntech Solar, a Rogue MPT-3024 Controller, and a Xantrex PW2000 Inverter