Pex Pipe Leaches Carcinogens Into Drinking Water

 I found this alarming article demonstrating that pex pipe leaches carcinogens into drinking water.

People who call me about water purification often ask what type of pipes I prefer in a home. My answer is copper. Some people think that copper leaches into their water but that is typical only when there is low pH water. Older copper pipes of course use lead solder and the lead is a problem if it leaches into your water.

In any case I prefer copper to the newer pipe options that are cheaper and easier to use.

One popular pipe these days is pex. I recently researched leaching in pex pipes and found this article clearly showing the pex pipe leaches carcinogens into drinking water. If you have a newer home I urge you to read it:,-chemicals-above-health-standards-caused-by-green-building-plumbing.html

New pex pipes can leach both toluene and ETBE, volatile organic compounds that are considered carcinogenic. These start at pretty high levels and decrease as the pipe gets older.

The information that is new to be is two-fold:

Some types of pex are worse than others…doesn’t name them in the article.

Leaching starts out incredibly high and then drops over 30 days, but there are no longer terms studies yet. (that I know of). At 30 days the numbers are still very high.

A kitchen water filter will remove these but it is important to change filters frequently.

Kitchen Defender water filter

Carbon filters, such as my Kitchen Defender, at the kitchen sink will remove both toluene and ETBE. The study does not name the other carcinogens, but presumably they are also volatile organics and therefore removable by carbon. What people don’t realize is that carbon filters have a limited amount of toxins they can adsorb before they stop working. This new information indicates to me that carbon filters will be used up long before estimates based on removing city chlorine.

Here’s a study that criticizes the methodology of the Purdue study above: 

And another document on the safety of pex as determined by NSF:

Frankly, the fact that NSF does not like the procedures used by Purdue does not offer me any comfort. The takeaway from this for me is that in a new house I would suggest you change your filters 3 times per year and then go to annually replacement after that first year. Until more studies are released this is just a guess on what you can do to prevent drinking these carcinogens.


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About James McMahon

Studied ecology at the University of Illinois, mountain survival at Eastern Washing University, Deep Ecology at Naropa, River Ecology with The Nature Conservancy and Luna Leopold
This entry was posted in Best Water Filter, Healthy Drinking Water, Reverse Osmosis and tagged . Bookmark the permalink.

1 Response to Pex Pipe Leaches Carcinogens Into Drinking Water

  1. CQHS says:

    As a new home owner, that’s some seriously disturbing information, but I’m grateful to you for sharing. We do have an under sink water filtration system, and this is very motivating to make sure that we are changing out the filters regularly. Thank you for posting.

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