Reverse Osmosis and Copper Pipes

Did you know that some piping coupled with RO water would actually produce undesirable effects? This article will cover the information you need to know about RO water and proper piping.

Reverse Osmosis (RO) Water

First, let’s talk about regular water. Have you ever heard that water is the universal solvent? Water is great at taking substances and dissolving them. The more substances that water has dissolved in it, the less it will try to dissolve other substances. The unit that is used to measure this, is known as TDS – total dissolved solids. Water with a high TDS won’t dissolve and absorb as many substances as water with a low TDS. Make sense?

When the piping that the water is flowing through begins to “dissolve” into the water, it is known as leaching.

Okay, now for RO water. Reverse osmosis produces the highest quality of water available for residential applications. It produces water that is very low in TDS, often with about a 95% reduction. And that is why this article exists, when using RO water, one must be cautious about the entire flow of the RO water after the system, including the tubing, fittings, and faucet used that comes in contact with the RO water.

Whole-House Plumbing

You may be asking “What about my plumbing? The water I shower in?”.

The reason that most homes, even with older iron galvanized plumbing, don’t experience any leaching is because the TDS in the municipal water is so high that the water doesn’t try to dissolve the pipes. This is also true with homes plumbed in copper, PEX, and PVC – the TDS of municipal water is high enough that it doesn’t cause any leaching. Not only that, PEX and PVC is pretty good at resisting leaching.

Copper Pipes

Copper is one of the materials that easily leaches into low TDS water. The copper will not only leach into the water (which copper poisoning is detrimental to human health) , but the low TDS water will also cause “pitting” in the copper pipes that leads to pin-hole leaks.

Okay, what does all of this have to do with RO water?

RO water is low enough in TDS that it will cause copper leaching.

Other Problem Piping for RO Water

Of course, the worst type of leaching that comes to the top of mind is lead leaching. This is actually what happened in Flint, MI, it wasn’t that the source water had lead in it, or that they weren’t removing lead in the filtration process, it was the old pipes that were distributing the water had lead solder and lead-lined pipes that began leaching into the water.

The best way to make sure that your RO water isn’t leaching from your pipes is to use RO approved tubing.

What Pipe Material is Good for RO Water?

Polyethylene tubing is the best material to use for RO water. It not only has advantages for resisting leaching, but is also easy to run through crawlspaces and and behind walls with the assurance of no leaks.

What About Whole-House RO Systems?

We do not recommend whole-house RO systems. The cost/benefit ratio is not there, and the benefits of shower and sink water being at the high level of purity of RO water is possibly not beneficial at all. We only recommend high-purity RO water for drinking and cooking. It’s natural to bathe and wash in water that has regular amounts of TDS (Total Dissolved Solids).

Reverse Osmosis Faucets

Like mentioned earlier in this article, the faucet that RO water is flowing from is important. RO faucets are specially designed to not allow for leaching, most often using ceramic internals. RO faucets are made with a wide variety of designs that can match your primary faucet allowing for a pleasing aesthetic.

Want to learn even more about whole-home water purification in Knoxville and Nashville? Check out our Knoxville and Nashville Residents Guide to Water Purification.

You can also contact our team and we would be happy to answer any questions you might have!