I've learned that letting metal contact reverse osmosis filtered water is generally a bad idea as it corrodes the metals and leaches them into the clean water supply.

However, I'm having a hard time finding a fully plastic 1/4-in compression fitting (1/4-in female to 1/4-in male) to connect my RO line to my refrigerator. Should I be concerned about the copper insert that will be in contact with the RO-filtered water? Will it affect the integrity of the connection and/or the water quality?

  • Ha, thanks Ecnerwal. I usually change a few unimportant words when editing something like that. I certainly want to keep leeches out of the fresh water supply though. Corrected. – glenviewjeff Jan 13 '14 at 3:18

Here are some that appear to be fully-plastic, and/or plastic + stainless steel

Without knowing what particular fitting you need (1/4 compression to what?), hard to get more specific than that. Full plastic fittings are out there, and really are what you want, as RO & DI water do love to eat anything that will give them ions. My reading on the above fittings is that the stainless (which is as good a choice as you get in metal, though aluminum may also work well from what I recall of an old lab D.I.W. system) is not in the normally wetted path.

Here is another supplier's nylon/polypro fittings:

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    Yup those are the fittings used, I think I seen them in local local hardware store also. I won't mention the names but the national chain stores should carry them. Incredibly easy to install, nice even, square cut on the pipe, push it on fully, done. – Jack Jan 12 '14 at 23:00
  • I did find one at Lowe's after writing this, but the threaded end of the compression fitting was oddly the wrong size once I got home. The package had been unopened but was clearly marked 1/4-in. I think the threaded end was actually 3/8 or 1/2. Incidentally, I think I'm going to cut the plastic hose on my fridge and just get a push-fit union because I think they probably already used metal ferrules inside the compression fitting attached to the fridge hose at the factory. – glenviewjeff Jan 13 '14 at 3:22

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