Even if you buy a brand new garden hose, it’s not clean; they’re made from materials that leach chemicals into the water. Once you get them out into the yard, they might be left partially empty with one or both ends open, allowing bacteria and mould to grow, letting insects in, etc.

If you go to a hardware store, you will find there are potable water hoses, they’re usually white with a blue stripe. They are made from food-safe materials and meant to transport potable water. Care still needs to be taken to not allow bacteria growth, but not really any more than a re-usable straw.