Watching a crew try to use residential PEX for a 4-story office building in Tempe

Terry Rivera · 2026-04-01T05:40:04.340511+00:00

The pressure drop across those long runs will be a nightmare in two years, and I've seen it fail inspection three times now. Anyone else had to fix this after the fact?

angela_jackson5mo ago

Actually, the new PEX-A stuff with the bigger inside diameter handles long runs way better than the old stuff. If they oversize the main lines a bit and use a good manifold system, the pressure drop isn't that bad. Some inspectors are just stuck on copper for commercial jobs.

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ruby5615mo ago

Upsized the mains and it passed last year!

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the_sam5mo ago

Heard a contractor on a podcast last week talking about a retrofit job just like this. They had to rip out all the PEX in a small apartment building because the pressure on the top floor was a joke. Took them weeks to re-pipe the whole thing with the right stuff. Honestly seems like a huge gamble to save a few bucks up front.

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