PEX - https://en.wikipedia.org/wiki/Cross-linked_polyethylene. It's well-established technology for indoor plumbing. It's not as flexible as a garden hose, but it is suitable for potable water. It's primary drawback is UV breakdown -- you can't use it where the sun will see it.
UV breakdown is easy to address with a sheath, but it's not nearly flexible enough for garden hose use. I have only used PEX-C, I hear PEX-A is more flexible, but it would have to be more than I think it is.
They make drinking water hoses for RVs. Could probably just buy one of those. Something like this: