I've been curious about the pex stuff as well. From what I've heard it's been used in Europe for quite some time. Additionally, I think it can be pulled through non-conditioned space (the attic space) since it expands with frozen water rather than bursts as does copper. Not sure if that's all correct, just what I've heard. Home Depot is now selling the sharkbite fittings that are supposed to be able to be used on pex and copper. I like the idea of the pex setup with what turns out to be a "circuit board" for your water system. I've no personal experience with it - the bad taste aspect seems worrisome. Cu is still the best but the cost has gone through the roof on it and pex is less labor intensive as well it seems.

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-livin' in the terminally flippant zone