Hello John Lee,
The potential problem with a "garden hose" is that you don't know what it is made from. It is quite common to use materials and chemicals in the manufacture of none food grade plastics, that can be harmful.
You will see from time to time postings about "Tainted Water", and these often refer to a TCP taste. This is causes by a plasticiser used to keep the plastic flexible, but it should be chemically fixed, so it does not taint the water. Other problems can result of the plastic being slightly porous, which allows algae and other nasties to lock into the plastic, and can therefore multiply and potential get back into the water supply.
The yellow colourant used in some plastics is derived from cadmium a highly toxic substance.
So you can begin to see that none food grade product can be quite unhealthy.
Hope this helps.