It is safe, the only thing is the smell, I use a white hose just because I had a travel trailer and you can tell the difference when using a standard green garden hose. Have you ever taken a drink from hose you will know what I am talking about, it will not hurt you just an added something.
I use a white hose as well without any ill effects. It's drinking grade and only cost a little more that the regular garden hoses. It's still MUCH cheaper than a python.
I flush mine out before using it. Mostly because it helps start the siphon when I'm back upstairs.
Here are a few shots of the DIY python. The hose is made with antimicrobial materials (the company says it protects against bacteria, mold and mildew). It's a lead free construction.