There have usually been falsehoods in the replies.
Plumbing is generally polyvinylidene fluoride, polyperfluoroalkoxy, ethylene chlorotrifluoroethylene. Original post when full of falsehoods, as stated by anyone else. Put a brass or iron bolt in distilled water and see what happens compared to tap water. Then again, impurities from the water shall leave residue on evaporators in the cooling wers and render them crappy. So here’s a question. Have you heard about something just like this before? Exotic plastics do not think to be used, similar to PFA, PVDF, Halar, etcetera doable exception probably was in a fab of a semiconductor plant. Then again, it shall not corrode it. It must leach some silica and boron, they practically need use peculiar glass, whenever having said this. With all that said. Distilled water is even made in glass stills for laboratory use. Authority plants do not use UPW cause tap water is more corrosive. Known all steam powered plants use UPW, because residuals should form on turbine blades and throw them off balance and destroy them. One can not compare tap corrosiveness water and UPW. Although, after all, HPLC and LCMS grade water is placed in glass containers. Seriously. LCMS grade water sitting in lab for over years. We use polypropylene, PEX, and even PVC. UPW should be corrosive to various different metals as it forms carbonic acid when exposed to air.