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.

6 Responses 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.

  2. BE says:

    I searched this subject because I had a hunch that Pex would act the same as other plastics in contact with water!!!
    As for “odor”… detectable or not… do so-called regulators think chemicals are not absorbed by lung tissues???
    Thank you!!

  3. Jennifer Richmond-Ananbeh says:

    I’m also extremely disturbed by this study and it’s findings. We just had our water line replaced by the city during a “lead removal/prevention project” for our neighborhood. (Of course it was at our expense.)
    I recall there being blue flexible piping rolled up like a hose in our yard the day they installed. I was curious about it, but didn’t think much past that. Until I stumbled upon an article describing PEX and its dangers. Now, as I am preparing to shower- I am having a small anxiety attack. I have Lupus and am especially sensitive to chemicals and toxins. I have a water purification system for our kitchen faucet and fridge water/ice maker. However, not the showers. As skin is the largest and most porous organ in our bodies it can easily absorb those toxics while showering.
    I purchased a whole home purification system (7 stage?) but the tank is small for showers and appliances. Is it as easy as purchasing a larger reservoir tank to connect for the whole house?
    Clearly this will be all I think about as I take my deadly shower. ☹️

    • A shower using my Urban Defender whole house water filter is a joyous experience….to feel natural water again without the harsh chemicals as well as those you cannot detect.

  4. Roon Dog says:

    As a Professional Engineer I am very familiar with the NSF and their safety standards. They really are the gold standard for potable water. When they say that this Professor’s class at Purdue used questionable methods, you can rely on that in my professional opinion.

    • I hear you although there is another prominent scientist who comes to the same conclusion. You can find her via google. I lean toward the side that says we often do things which cause harm and don’t even know it.

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