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I do not see why extremely pure water would leach metals any more than tapwater would. Chemically it should not matter. All species will reach equilibrium betwe

I do not see why extremely pure water would leach metals any more than tapwater would. Chemically it should not matter. All species will reach equilibrium between the surface of the container and the liquid and if dilute they will not care about one another. That equilibrium will be reached faster if the temperature is higher. What is true is that you should not drink hot water from pipes because hot water does leach metals, tapwater or otherwise.

michaelcampbell 10y ago
Was this not the issue in Flint, Michigan with the water leaching lead because it DIDN'T have something in it?
- vessenes 10y ago
  No, the water there was more acidic than the prior water the system used, causing leaching.
  - michaelcampbell 10y ago
    I see; thanks.
ridgeguy 10y ago
Very pure water is corrosive. I built a CVD lab that had aluminum deposition chambers plumbed into a DI water cooling system. The water was fed from a purifier that provided 18MΩ-cm water. The water corroded the aluminum chamber cooling passages, leaving aluminum hydroxide behind. This conversion of metallic aluminum to a gelatinous, clogging hydroxide was what alerted us to the problem. Feed pressure (regulated) was fine, but flow rates fell and chambers heated up. We had to wire brush all cooling channels, a total pain. We ran on tap water for a couple of weeks while we researched the issue, and had very little corrosion but had other issues (mineral deposits). Finally, we reverted to 18MΩ water and added ~10% volume of ethylene glycol (antifreeze, basically). Once we "degraded" the water purity with glycol, our corrosion problems stopped. It was very counterintuitive. Here's an industry source that has a little bit to say about the corrosive properties of pure water: http://www.lytron.com/Tools-and-Technical-Reference/Application-Notes/Deionized-Water http://www.lytron.com/Tools-and-Technical-Reference/Applicat.... Given the industrial importance of the problem, I'm sure there are in-depth chemistry explanations. Haven't pursued them.

michaelcampbell 10y ago

Was this not the issue in Flint, Michigan with the water leaching lead because it DIDN'T have something in it?

vessenes 10y ago
No, the water there was more acidic than the prior water the system used, causing leaching.
- michaelcampbell 10y ago
  I see; thanks.

ridgeguy 10y ago

Very pure water is corrosive. I built a CVD lab that had aluminum deposition chambers plumbed into a DI water cooling system. The water was fed from a purifier that provided 18MΩ-cm water. The water corroded the aluminum chamber cooling passages, leaving aluminum hydroxide behind. This conversion of metallic aluminum to a gelatinous, clogging hydroxide was what alerted us to the problem. Feed pressure (regulated) was fine, but flow rates fell and chambers heated up. We had to wire brush all cooling channels, a total pain. We ran on tap water for a couple of weeks while we researched the issue, and had very little corrosion but had other issues (mineral deposits). Finally, we reverted to 18MΩ water and added ~10% volume of ethylene glycol (antifreeze, basically). Once we "degraded" the water purity with glycol, our corrosion problems stopped. It was very counterintuitive. Here's an industry source that has a little bit to say about the corrosive properties of pure water: http://www.lytron.com/Tools-and-Technical-Reference/Application-Notes/Deionized-Water http://www.lytron.com/Tools-and-Technical-Reference/Applicat.... Given the industrial importance of the problem, I'm sure there are in-depth chemistry explanations. Haven't pursued them.