I don't have the answer to your question, but I DO have a hose recommendation. I am ridiculously enthusiastic about this super-safe, USA-made, drinking-water-safe polyurethane hose from Water right: http://www.waterrightinc.com/collections/watering-accessories/products/slim-lightweight-polyurethane-garden-hose-100-ft

I wrote a blog post about it here: http://ourgreendreamhome.com/2014/04/12/i-love-this-best-hose-ever/

The hose and the water that comes out of it has NO chemical stink, and since it is truly thin and light, it's very easy to use, even the extremely long 100ft lengths that we use around here.

(No, I don't work for the company! I just like their hoses!)

I was looking at the Flexon company and they don't seem to say anything about using antimicrobial agents being used.

Here is a link that might be useful: http://www.flexonhose.com/medium.html#allweather

Pretty much any rubber/vinyl hose is going to have water tasting like plastic if you leave it in there or let it get hot.

GreenDreamHome's hose is probably a better hose if you're worried about "chemicals".

You will find Triclosan, an antibacterial, in many consumer products that are sold to fight "germs". Studies show it is no more effective at controlling those "germs" then just plain soap and water, but the low levels of these antibacterials is allowing the disease pathogens to develop immunities to them.
All water hoses will have some kind of problem that can be resolved by allowing water to flow for a minute or two to flush the hose, and draining that hose and coiling it out of the sun when not in use.

Funny how I emailed the Flexon company to ask about biocides in their hoses and they never got back to me. This company doesn't label their products as having the chemical added, but I wanted confirmation.

"Studies show it is no more effective at controlling those "germs" then just plain soap and water"

Surely you can link to those studies.

There's a whole ton of them that say its way more effective in killing things than soap. What's in question is whether or not you need to kill things.