It would really depend on your water source I believe. Our water is well water and is clean as a new day. Downtown however people don't want to use the city water because it's not treated as well as they'd like and sometimes smells funny. They put a filter on their outdoor hoses, it can be gotten at any home improvement center in the watering section. I found a good one in the microwatering supplies.
I have also heard about not drinking water out of a garden hose. Something to do with the plastics in the hose. I figure if they can drink out of a poopy puddle what could a hose hurt. I have been drinking from a hose for years and besides my memory loss, stuttering and twitching I don't see the difference. John