Piping for New Construction – Plastic vs. Copper

by / Friday, 30 October 2015 / Published in Green Building Consulting
Plastic vs. copper

Piping for New Construction: Plastic vs. Copper

What Do We Know – What Should We Do?

Water, it has been revered since the beginning of time. It sustains and nourishes us; we couldn’t live more than three days without it. Fortunately in the Western World it is readily available. It is so seamlessly intertwined with our daily lives that we rarely think about the system that delivers it to us. However, the more we know about our water system the more empowered we are to make sure we are getting the highest quality water possible. Which type of piping is better: plastic vs. copper .

This blog post will focus on information researchers have discovered that highlight the safety issues surrounding different types of potable water piping material, namely HDPE, PEX, PVC, and Copper Piping. Weighing the risks, it will pose the question of which piping material should be used for new construction and renovation projects. If you have any thoughts or considerations on the matter please suggest. Though the findings are compelling and an important part of the puzzle, they are in no way comprehensive. More studies and respective innovation are needed to fix the problems and create a better system.

 

plastic vs. copper

PVC Plastic Water Faucet

Plastic Piping

Okay, let’s address plastic piping first, specifically HDPE, PEX, & PVC.

Plastic piping was introduced to the United States in the mid 1980’s and has become increasingly popular – not surprising. Plastic piping is easy to install. Its route through the building can be more versatile and potentially contribute to making the building more holistically designed—(suggestions and case studies that have done this are welcomed). Plastic piping is also less expensive which obviously helps with budgeting and money allocation. It can also be used for 50 years or more.

However studies are showing that chemical compounds found in plastic piping are leaching into our drinking water. Though testing is still in its nascent stages, studies have concluded that High Density Polyethylene (HDPE), Cross Linked Polyethylene (PEX), and Polyvinyl Chloride (PVC) pipes, release both regulated and unregulated VOCs (volatile organic compounds), unidentified contaminants, and assimilable organic carbon (AOC) that can possibly lead to microbial growth.

A 2015 study conducted by Andrew Whelton and his associates at the University of South Alabama & Purdue University, is a particularly good source of information. The study tests for VOCs, AOCs as well as other compounds in PEX, HDPE, PVC and PP pipes. The VOC testing is generally aimed at PEX piping. Additionally, the paper expands its breadth beyond its results by referencing the findings of other studies that discovered similar contaminants.

Here is the link to read the study in AWWA (American Water Works Association) Journal: PEX and PP Water Pipes: Assimilable Carbon, Chemicals, and Odors

To briefly surmise: Whelton and his team’s results showed the presence of VOCs including ETBE, cyclohexane, toluene, and xylene in the water of eight PEX pipes over a 30-day cycle. According to the paper, “ETBE, toluene, p-xylene, and unspecified xylene isomers have been previously found in PEX contact waters.” These studies include: “Skjevrak et al., 2003; Koch, 2004; Durand and Dietrich 2007”. Whelton’s results indicated that VOCs were higher in the beginning of the period, and in some cases, were not present at the end. Only ETBE and cyclohexane remained detectable on day 30 but these were below NSFI 61 standards.

 

The studies referenced above differed for PEX piping. For instance the 2014 study by Kelly et. al. showed the presence of both toluene and ETBE (65 ug/L) on day 30. Durand and Dietrich’s 2007 work showed ETBE levels ranging from 0.14 ug/L to more than 100 ug/L; and a particularly alarming test at an Oklahoma home found ETBE levels at 22 ug/l and toluene levels at 80 ug/l after a year – these levels are above OTC thresholds. In addition to PEX, a study in Norway presented at the 20th No Dig Conference at Copenhagen (2002) (link below) found that “five out of seven tested brands of HDPE pipes showed unacceptable TON values of test water.”

Here is the link to the No Dig Conference study entitled:

Potential water quality deterioration of drinking water caused by leakage of organic compounds from materials in contact with the water.

What can be determined by these varying answers? In the case of Whelton’s, is PEX piping really all that dangerous if only a few VOCs are present after a 30- day cycle- and are below NSFI 61 standards ? Though we should eventually find this answer out, the conclusion does not account for the other instances VOCs were found. Is there a way to shorten the leaching period, or better yet eliminate leaching all together?

Let’s move on to AOCs.

Whelton’s study found that six of the eight PEX pipes had AOC levels exceeding 100 ug/l on day 7 of the cycle- just to note 100 ug/L of AOC is when coliform detection occurs. By day 28, however, none of the PEX pipes exceeded the microbial regrowth threshold. Similarly AOC levels for HDPE and PVC brands increased by 22% ug AOC/L and 58% ug AOC/L respectively over the course of the 28-day cycle but did not exceed 100 ug/L on day 28. The study listed at the No Dig Conference (referenced above) states that “ PVC and PEX have a higher biofilm growth on their surfaces than the glass reference,” however in this study, the AOC presence also diminished over time.

Similar to VOCs, AOC results vary within each study as well as when compared to other studies. Do AOC levels pose a risk if they reach the coliform threshold in the beginning of the cycle but not at the end? Should we be weary of AOC presence altogether? Can the quantity in the pipe grow after thirty days?

More research needs to be done to ascertain what’s going on. Compounds that we don’t want in our pipes are being found. In addition to the presence of VOCs and AOCs, Whelton’s study detected that “a significant number of unknown compounds spanning from low to mid molecular weight are present in PEX pipe contact water.” How do we evaluate these mysterious chemicals? Similar to VOC and AOC findings, what are the health implications?

We have to find this information out if we can truly vouch for plastic pipes’ use. It’s difficult and disrupting to the industry, but if we can avoid ingesting volatile organic compounds that are carcinogenic, endocrine disrupting, and neurotoxic in our pipes, we should – even if they are in small quantities. Similarly it’s obvious that we don’t want bacteria forming in our pipes. Therefore, we need to fully understand what causes AOCs to form and how to prevent them. As for the contaminants that we do not know – well that just opens up a whole can of worms to be figured out.

 

plastic vs. copper

Piping for New Construction: Plastic vs. Copper. Copper Plumbing

Copper Piping

The primary alternative to plastic piping is copper piping. Copper piping has been around since Ancient Egypt; it is a natural resource, existing in the earth’s crust, plants, animals, and humans. Copper is antimicrobial and does not pose the same risks that plastic pipes do ie, VOCs, unknown contaminants, & AOC growth. With that said, copper has its own problems.

According to the EPA copper can “leach into water primarily from pipes, but fixtures and faucets (brass), and fittings can also be a source.” The EPA also explains that, “the amount of copper in the water depends on the types and amounts of minerals in the water, how long the water stays in the pipes, the water’s acidity, and its temperature.”[1] Over consumption of copper can lead to nausea, gastrointestinal problems, liver damage, and kidney disease, amongst others. [2]

The EPA has limited the amount of copper leaching into drinking water to 1.3ppm.[3] Water treatment plants have added corrosion inhibitors such as fluoride to prevent copper pipe deterioration.[4] Additionally new legislation has mandated potable water pipes to contain less than 0.25% of lead, making copper piping safer than it was before.

Nevertheless, due to the fact that copper has more potential to leach into the water when it is idle (more than six hours), one should run the drinking water for 30-60 seconds before consuming.[5] Additionally, according to the Minnesota Department of Health, hot water dissolves water more than cold water. Thus if you need hot water for cooking, you should heat cold water over the stove rather than getting it directly from the faucet.

According to the Action Water District “after the initial leaching” of copper pipes, “the inner surface of the pipes forms a hard surface that should reduce further leaching.”[6] However, as of now, there has not been a fool-proof way to prevent copper from entering the pipes from within a home.[7] As a result there are different treatment options available such as reverse osmosis, ultra-filtration distillation, and ion exchange that one should consider.[8] The CDC recommends getting your pipes tested by a licensed professional to ensure that copper levels do not exceed safety levels.

Conclusion

Unfortunately we do not currently have pipes that are 100% safe. As a result we must choose the best options available. After reviewing the research for plastic vs. copper, copper piping appears to be the system that is the easiest to control. Water filtration methods as well as new lead standards help ameliorate heavy metal toxicity risk. We do not have enough information on the dangers of plastic piping. Studies have shown alarming evidence of VOC presence, unknown contaminants in drinking water, and Assimilable Organic Compounds that can lead to deleterious bacteria. There are too many question marks to adequately enact safety precautions and therefore plastic piping cannot be fully trusted.

Sources on how to make plastic and copper piping safer are welcomed. The more we work towards a solution instead of defending the status quo, the closer we will be to getting the quality water we want and rely on.

 

[1] http://water.epa.gov/drink/contaminants/basicinformation/copper.cfm

[2] http://www.health.state.mn.us/divs/eh/water/factsheet/com/copper.html

[3] http://water.epa.gov/drink/contaminants/basicinformation/copper.cfm

[4] http://www.cdc.gov/fluoridation/factsheets/engineering/corrosion.htm

[5] http://www.health.state.mn.us/divs/eh/water/factsheet/com/copper.html

[6] http://www.actonwater.com/water-quality/copper

[7] http://www.documents.dgs.ca.gov/bsc/prpsd_chngs/documents/monograph_reference/Freidlander%20Ref%20letters/Summ.%20of%20Lit.%20Search%20Copper%20Leaching%20_7.pdf

[8] http://www.cdc.gov/healthywater/drinking/private/wells/disease/copper.html

 

 

 

 

 

 

27 Responses to “Piping for New Construction – Plastic vs. Copper”

  1. […] PEX supply lines Soldered copper tubing has been largely replaced by polyvinyl chloride (PVC) and chlorinated polyvinyl chloride (CPVC) tubes and fittings. Both of these synthetic plastic polymers are said to have latent environmental problems (see this article at Healthy Building Science). […]

  2. Amanda Hill says :

    I agree with Tom on this post. There can be a good debate about pro’s and con’s of copper and PVC products, but the reality is these products have each been used for decade’s and when you think about the delivery methods of potable water to our homes it touches copper pvc, galvanized steel, iron, etc.

  3. Katie Bachner says :

    Hi, thanks for your comment, and sincere apologies for the very delayed response. Stainless steel piping is said to be more corrosion resistant than copper. I have read that Grades 316/316 L are more resistant to chlorine than other types of stainless steel piping. Please find a link below to a study done on stainless steel by the International Molybdenum Association on stainless steel pipes. http://www.imoa.info/molybdenum-uses/molybdenum-grade-stainless-steels/water-distribution.php#. I have read that stainless steel is more difficult to work with than copper but I do not know this from first hand experience. Though most likely biased here is a link to the British Stainless Steel Association’s report: http://www.bssa.org.uk/cms/File/BSSA%20PLUMBING%20P.1-4.pdf. I have not read enough studies to state whether stainless steel is better than copper – but it definitely has its pluses. I hoe this helps you get started !

  4. Trey says :

    Since this article was posted I have read about Hyperpure, which is another option that is installed like PEX but is chemically polyethalene (PE-RT) which is recyclable and more durable and chlorine resistant. Buildinggreen.com did an article on it in June. Do you guys know anything about it or its chemistry in regards to leaching or any of the studies you listed above? I am wondering if it is a better alternative to PEX but still maybe not as good as copper, or just not perfect. What would you recommend in general? A whole house filter, plus whatever plumbing and a drinking water filter at the end? We use a Big Berkey right now for drinking water but it would be nice to not have to do that. Thanks for the work you are doing!

  5. […] Piping for New Construction – Plastic vs. Copper – Have we as a society tested stainless steel pipes as opposed to either copper or plastic piping. A crazier idea would be to even see if titanium is a future possibility. […]

  6. Katie Bachner says :

    Thanks so much for your comment. I completely agree- that is why the more we know the more we can progress. The best we can do is be informed and choose the healthiest path.

  7. Alex Stadtner says :

    And what we think is safe now … may someday become known to cause harm. That’s what happened with lead, asbestos, tobacco, etc.
    We cannot get stuck in analysis paralysis. Decisions about healthy building materials must be made. And we go with the best information at our disposal at the time.

  8. It’s interesting to note that pipes can’t all be 100% safe like you said. There’s nothing in the world that’s 100% safe if you think about it. My point is that shouldn’t hold someone back. I agree that copper would be better. I’m going to link my brother to this site.

  9. Katie Bachner says :

    Thanks for the comment:

    With all piping there are some installations that are better than others. Copper piping has obviously withstood the test of time – most say it lasts for 50 plus years. There are different types of copper for different applications- so you gotta be sure you have the right standard.

    While PEX piping is durable lots of brands have been found to leach chemicals as well as build up chemicals if they have not been flushed or filtered.

  10. greg sutherland says :

    If you’ve repaired three separate slab leaks in two years because builders used crap soft copper piping, you eventually come to the conclusion that PEX makes a lot more sense.

  11. Thinker says :

    Have we as a society tested stainless steel pipes as opposed to either copper or plastic piping. A crazier idea would be to even see if titanium is a future possibility. I know with cookware Steel and copper are said to leach into our food but titanium is said to be the only metal as of today not to. I understand the cost associated with titanium as well which is why I propose stainless steel. Of course to address the problem of receiving the water from the city in plastic pipes our couture will need to look towards closing loops. A quick example would be rain water. I understand not all places can live as laveshly as today because of how much rainfall certain areas receive but that would eliminate the contaminates from the city leaving you to only need to think about the piping you choose touching your water. It’s unfortunate that in 2016 we still have to choose between two evils and somehow have not found a proper solution.

  12. Sam Fisher says :

    If I was building my home from the ground up, I’d probably have to go with the copper piping. Mainly because it has more benefits and is more widely used. Even though copper can leach into the water, I think this would only be apparent in older homes where the pipes have been in place for many years.

  13. Katie Bachner says :

    Hi Tom,
    I’m sorry for your troubles. PEX is notorious for giving water odor, however, a few months is a long time for the water to still smell. Did you flush the pipes when they were initially installed? Has the water been sitting in the pipes for a long time aka do you turn on the respective faucet often? You can do a couple of things. One option is to get your water tested to see if there are chemicals that exceed NSF thresholds for potable drinking water. If dangerous chemicals are present you can replace the pipes, or get a water filtration system that is geared towards filtering out VOCS, bacteria and other pathogens. I recommend getting a filtration system in general.

  14. Tom Kastner says :

    Several months after installing PEX in our house, there is still a plastic taste in the water and it doesn’t seem to be diminishing. Never heard about the bio-slime inside plastic before. What’s the cure?

  15. Katie Bachner says :

    Thank you for this information Yamini and for linking to the study directly. It is great when we can fulfill our needs by respectfully using the properties of the earth as aids. Knowing that we can rely on copper to prevent deleterious bacteria from traveling through our pipes is major. Hopefully as the art of copper plumbing progresses, we will be able to prevent corrosion, and understand how to stop copper from deteriorating into the water. Exploring the inherent qualities of copper will take us closer to answering these questions.

  16. Alex Stadtner says :

    Hi Anne, Thanks. I think it may show-up in EcoDwell soon. But I cannot take credit for it – it was all Katie Bachner’s doing.
    Interesting point about the stray current and copper. I could write more about this… but will leave most the discussion for non-EMF-related comments when comparing plastic to metal piping. Thanks for sharing this Building Biology concept (EMF) in what is normally just a chemical/toxicology discussion.

  17. Anne Stewart says :

    Great article Alex. I thought very well-balanced and researched.

    One thing to add: there is a benefit in having plastic at some point in a house system if an electrical ground (from the electric panel) is required to be attached to the house plumbing system (as it is in Ontario). By installing plastic (a dielectric union) net current from the house electric panel and from other net current in the neighbourhood does not run throughout the house. I’ve found this a useful strategy to remove net current.

  18. Yamini Kumar says :

    Ancient Ayurvedic medical texts have recommended storing water in copper for a period of time and only then drinking it, which is kept as a daily practice in India especially. Now, current medical studies are supporting this ancient practice. According to a 2012 study published in Journal of Health, Population, and Nutrition, storing bacterially contamined water in copper for up to 16 hours at room temperature considerably reduces the presence of the harmful microbes. The study link >http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3312355/

  19. Alex Stadtner says :

    Interesting point about theft. That must be a regional phenomena, but it sure would be an unfortunate and unexpected job cost. I suppose the same argument against copper could be made for any high-end product or material made of valuable metal. There’s value in good materials and thieves are opportunists.

    You’re probably right about the relative risk of getting cancer from drinking from plastic piping. It’s just one more source of exposure to to carcinogens, estrogen-mimicking compounds, etc. But for folks following the precautionary principal – and for those fortunate enough to be able to afford an alternative – many opt to avoid plastic for potable water piping. We have some clients that have gone even further and avoided PVC in wire jacketing, electrical boxes and switches, flooring, bathtubs, appliances, etc.

    Your last comment about durability and resistance to rodents reminds me of another blog we wrote about Best Practices for Residential Wiring, in which David Sasse references your little angels as one reason to opt for metal-clad (BX) wiring instead of standard Romex.

    Thanks for writing in, and good luck building the healthiest, most efficient, and durable buildings you can. It aint easy.

  20. Pamela Vivion-Brooks says :

    Aside from the cost concerns regarding copper, it is not only very expensive but highly susceptible to theft which can effectively double the cost should theft occur. I’m no chemist, but I can safely assume that there are far worse air and food borne carcinogenics that will kill us before our water pipes do. Copper is also useful in areas that are prone to rodent infestation because plastic pipes can easily be chewed through by the little angels.

  21. Alex Stadtner says :

    Right. Better yet, suck your synthetic juice concoction through a PVC pipe for a straw. Even though plastics are a 20th century industrial-chemical phenomena, I’m certain this is how we evolved to hydrate.

    P.S. Excuse the sarcasm. Sustainability consultants and public health advocates I know suggest minimizing contact of potable fluids with most plastics, especially PVC.

  22. Scott Jung says :

    So I run tap water into a Plastic Container for water or Juice concentrate, pour out the contents into a plastic cup…….

  23. Alex Stadtner says :

    A couple more comments on copper:

    1) Another consideration with copper is what solder and flux is specified. As we discussed in a previous blog, “lead-free” is not “100% lead-free.” When we perform lead inspections it often involves testing potable water sources – usually a kitchen tap – at the “first flush,” and again after allowing the water to run for a few minutes. This first-flush test helps us determine if the pipes/fittings/solder are contributing to lead levels in drinking water. The second test helps evaluate the supply water from the municipality or well. If the first-flush is high we often first look to the solder, which can easily be tested for lead content. Allowing the water to flow for a while before filling a cup is an easy mitigation strategy, although not the best for water conservation.

    2) Some municipalities, such as Palo Alto, are moving away from allowing copper on roof-tops or in gutter systems due to concerns about aquatic toxicity. While aged (oxidized) copper may be harmful to aquatic life and this should not be ignored for exterior applications, in our years of testing potable water we have never found copper in harmful quantities.

    Great blog, Katie. Thanks for getting the dialogue started.

  24. Katie Bachner says :

    To address the other post – sorry I do not know your name – please see the article’s added links. I hope this helps clarify some of the points.

  25. Katie Bachner says :

    Thanks for the comment Tom. This article has been revised since your last post as a means to go into copper piping more thoroughly as well as to cite data from plastic pipe studies. I hope you find the added information and links helpful.

    To address your comment, copper ingested in large quantities can cause gastrointestinal problems and organ disease (amongst others). The EPA has tried to regulate the amount of copper in potable water but can only do so much. I think that what you are doing re: flushing is smart. I also recommend looking into filtration methods that have been created to mitigate heavy metal toxicity (referenced in blog).

    I am trying to get in contact with someone from the copper piping industry who can help shine light on how we can prevent copper from leaching into our drinking water. I will post with new information as soon as I have it. Hopefully this is only the beginning of the conversation.

  26. Thank god you folks are looking out for us. says :

    Did you ask the water municipalities ” folks” how many miles yes miles of plastic they have buried in the ground before you connect to copper? But as the animals have copper in them it must be safer to drink from a puddle? Is this real research? I am unsure as to what your motives and lack of research are. what testing agency conducted your test? Can we see the results or could your post them to the AWWA, NSF, and other pertinent agency’s so we could make an industry wide adjustment?

  27. Tom Gocze says :

    Interesting article. It does seem slightly one sided. How about copper by-products, which have a natural biocide effect, which are ingested? How does this challenge human health?
    The plastic and copper manufacturers have been going back and forth as to who makes the more dangerous product for a long time.
    I use both materials and will continue to flush the lines when drinking or cooking before use.
    There does need to be more research on the bio-slime that forms inside plastic tubing, as well as the corrosion materials that show up in copper tubing.

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