Hokay. I'll chime in. RO systems as found at home probably remove about 90% of all minerals and also remove all chlorine if an activated charcoal outlet filter is present and functional. This leaves enough minerals to provide some taste and defense against leaching. RO water is not distilled water. Distilled water would tend to aggressively leach out about any metal. Boiler makeup is typically deionized water (which is like distilled water-just made by a chemical process instead of a distillation/condensation heat process), then treated with specific chemicals to prevent corrosion-another word for leaching. Our house has a typical home water softener that does not reduce mineral content, but exchanges sodium for calcium. Sodium deposits are more soluble than calcium deposits. I use the softened water to wash our Chrysler 300 and it still leaves water spots, but they are easier to chamois off. We also have an RO system that processes the softened water before sending it to a small sink tap and the icemaker. Our house has an island counter in the kitchen and has a copper tube running from the RO system to the refrigerator on a far wall. The tube is buried in the concrete slab, so I just connected it up and am using it. Ten years later, no problem with icemaker or connections. We refill those plastic water bottles from the RO tap at the sink and we ain't dead yet. But, we are on our third water heater in ten years. As the water is heated, some of the high mineral content precipitates into the bottom of the tank. I know that I should be draining the tank and sludge more regularly, but this is some indication of how even softened water might act in our Chrysler 300 radiators. We also use RO water for house plants, coffee, tea, our Chrysler 300 6-Volt battery and makeup water to mix with antifreeze for our Chrysler 300 radiator. I believe our RO system is right for us, our plants, coffee, tea and Chrysler 300 radiator and battery. A nearby small local community has switched to a centralized water softening system for their municipal water as it is sourced from wells. The EPA is on their case as their sewage effluent is occasionally above very stringent limits for copper content. There is strong evidence to indicate that the ion exchange systems used in our homes does result in some copper being leached out of house piping. This may be as much an electrolytic action as strict chemical action, but it is happening. This is a major reason for requiring plastic piping in homes. But, there is some indication that some nasty stuff may be leached out of plastic water piping, also. Ethanol-enhanced beverages in glass containers may well be the best solution. Googling copper produced lots of papers, but there appears to be agreement that copper is needed by animals and plants and that many do not get enough. It is apparently possible, but unlikely, for humans to get too much copper and some health conditions require less copper, just like people with high blood pressure are encouraged to avoid the high-sodium softened water. I haven't looked, but the antifreeze manufacturer may have recommendations for what kind of water to use with their product. But, I'm sure the antifreeze manufacturer would prefer softened water to hard water and low mineral content water to highly mineralized "caliche" water. Different waters would be expected to react differently to the mineral/organic corrosion inhibitor chemicals in the antifreeze. Cu-300'ly, Rich Barber Brentwood, CA -----Original Message----- From: Chrysler300@xxxxxxxxxxxxxxx [mailto:Chrysler300@xxxxxxxxxxxxxxx] On Behalf Of james mcmullan Sent: Monday, February 11, 2008 1:23 PM To: Listserver Subject: [Chrysler300] About watter When i put a reverse osmosis system in, the paper work said do not plum the ice maker with copper.I sent for there kit to get all plastic fittings and tubing.It came with a brass fitting ? go figure .They claimed that the pure watter would, in time, leach the copper.the watter tests with zero parts per mil.particulates.As clean as distilled.I drink it but take meneral supplements.I use it in battery's but not the car watter system.Jim McMullan 300 F [Non-text portions of this message have been removed] To send a message to this group, send an email to: Chrysler300@xxxxxxxxxxxxxxx For list server instructions, go to http://www.chrysler300club.com/yahoolist/inst.htm For archives go to http://www.forwardlook.net/300-archive/ Yahoo! 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