Drinking water odors, chemicals above health standards caused by 'green building' plumbing

Drinking water odors, chemicals above health standards caused by 'green building' plumbing
Andrew Whelton, an assistant professor of civil engineering in Purdue's Lyles School of Civil Engineering and Division of Environmental and Ecological Engineering, is leading research into the effects plastic pipes have on drinking water in eco-friendly green buildings in the United States. Credit: John Underwood

Several types of plastic pipes in eco-friendly green buildings in the United States have been found to leach chemicals into drinking water that can cause odors and sometimes exist at levels that may exceed health standards.

Buildings are being plumbed with many types of plastic drinking water . These include crosslinked polyethylene (PEX), high-density polyethylene (HDPE), polyvinylchloride (PVC), chlorinated PVC (cPVC) and polypropylene (PP) pipes, said Andrew Whelton, an assistant professor of in Purdue University's Lyles School of Civil Engineering and Division of Environmental and Ecological Engineering.

Plastic pipes are generally less expensive, lighter and easier to install than metal pipes. A 2012 comparison showed PEX pipe was the least expensive among plastic pipes, costing 43 cents per foot compared to the most expensive metal, copper pipe, at $2.55 per foot. 

Thousands of dollars can be saved during construction by installing plastic instead of metal plumbing systems, and proponents assert plastic pipes require less energy to manufacture - generating less carbon dioxide compared to metal pipes - ostensibly making them a good fit for green buildings.

"Little is known about the degree to which plastic pipes sold in the U.S. affect drinking water quality," Whelton said.

He will detail research findings in a presentation during the 2014 U.S. Green Building Council's Greenbuild International Conference & Exposition on Friday (Oct. 24) in New Orleans with Rebecca Bryant, managing principal of Watershed LLC of Fairhope, Alabama. Some testing results were published online in September in the journal Water Research. There, the researchers describe drinking water impacts caused by six brands of PEX pipes available in the United States.

In the September study, drinking water was tested from a PEX plumbing system in a "net-zero energy" building in Maryland six months after the system had been installed. The testing revealed the presence of 11 chemicals that were PEX pipe ingredients and ingredient degradation products. Research with PEX pipes in the laboratory also showed that six brands caused drinking water to exceed the U.S. Environmental Protection Agency's maximum recommended drinking water odor limit, Whelton said. The U.S. EPA's maximum drinking water odor limit is a "threshold odor number" of 3, or 3 TON. Compliance is voluntary because the standard is based on aesthetic - not health - considerations.

Odor and chemical levels were monitored with and without chlorine treatment over a 30-day period for the six pipe brands. Chlorine, the most popular disinfectant chemical used in the United States, protects drinking water from disease-causing organisms as it travels to the tap. When chlorine reacted with chemicals leached by the , odor levels for one brand of PEX pipe tripled. While the total mass of chemicals leached by PEX pipes was found to decline after 30 days of testing, odors generally continued as the pipes aged, Whelton said.

A general assumption in the United States is that chemicals responsible for drinking water odors pose no health dangers. Although, several chemicals found in the plumbing research have regulated health limits, and one PEX pipe brand caused drinking water to exceed the ethyl-tert-butyl ether (ETBE) drinking water health standard. ETBE is a PEX pipe manufacturing byproduct with drinking water standards in New Hampshire and New York state.

When establishing the ETBE limit in New Hampshire, public health officials specifically added a 10-fold reduction to allow for its suspected carcinogenic potential. However, no federal drinking water standard exists, Whelton said.

The researchers found ETBE drinking water levels as high as 175 parts per billion (ppb) during the first three days of PEX pipe use and then 74 ppb after 30 days of use when the testing ended. New Hampshire has the most stringent drinking water health standard of 40 ppb. Michigan also has an ETBE standard, but it is based on limiting drinking water odor caused by ETBE.

The presence of drinking water odor can prompt homeowners to avoid their altogether.

"A contractor who installed PEX in parts of a million-dollar home in Oklahoma asked us for help because the homeowners reported gasoline-like odors in a bathroom's tap water," Whelton said. "The homeowners refused to take showers in the PEX-plumbed bathroom because they were concerned about their health."

By testing tap water from the home, Whelton's team discovered that toluene, a solvent used for plastic resin synthesis and ETBE were present above levels where odors would be detected. Neither toluene nor ETBE exceeded health standards, however. The gasoline smelling water was safe to use.


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Drinking water from plastic pipes - is it harmful?

More information: "Release of drinking water contaminants and odor impacts caused by green building cross-linked polyethylene (PEX) plumbing systems." Water Res. 2014 Sep 10;67C:19-32. DOI: 10.1016/j.watres.2014.08.051 . [Epub ahead of print]
Provided by Purdue University
Citation: Drinking water odors, chemicals above health standards caused by 'green building' plumbing (2014, October 21) retrieved 22 August 2019 from https://phys.org/news/2014-10-odors-chemicals-health-standards-green.html
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Oct 21, 2014
It was NEVER, EVER about being green. It was always a time and money issue in disguise with the builders. I guarantee all construction utilizing plastic piping will need a complete replacement before the 20 year mark, or perhaps earlier.

Oct 21, 2014
Green building using plastic pipes??? Sorry but there is nothing green about plastic.

Oct 21, 2014
It is not a "given" that copper lasts longer than plastic. Copper does wear away. One time I went to fix a "little" leak in a copper pipe in a 1970s home and found that the pipe was paper thin. Also, plastic waste lines will probably last longer than cast iron.

That being said, I would much rather be drinking copper oxide than plastic vapors.

Oct 21, 2014
Also, a 30 day test is unreasonable for new pipe. This is bordering on propaganda. Give us some data on a one year old system that has been in constant use and then we can make an informed evaluation of the dangers of plastic pipe.

Dumb people microwave their food in plastic every day. To me this is much more of a hazard than PEX pipe.

Oct 21, 2014
Having been in plastics injection molding and extrusion, I concur we should have no plastic in the water systems of our homes. Besides the carcinogenic monomers, there are mold releases, plastcizers, and other ingredients in the mix which can and usually do leach out.

Oct 21, 2014
Gkam is this a long term danger or do most of these chemicals dissipate in a year or so. Housing like everything else is a compromise between what is ideal and what is affordable. Yes, we can build the safest and most energy efficient housing possible but can we afford to purchase it?????????????

It all comes down to a cost/benefit ratio. What is the advantage of perfect housing if you cannot afford to live in it?

Oct 21, 2014
MR166. There is no fixed answer, even for known chemicals. The leach rates will vary due to temperature and pH, as well as other parameters. It will probably reach close to zero, after the near-surface chemicals go.

As for cost-benefit, perhaps you have not had a seriously-ill family member, due to something like this? A liver is a terrible thing to waste.

But you are correct in that C/B is what will happen.

Oct 21, 2014
Gkam all of life on earth is governed by a C/B ratio. As horrible as cancer is, starvation or freezing to death is worse. I know that judging survival on costs can seem harsh but nature is harsh and cannot be negotiated with.

Oct 21, 2014
MR166 - If you look at the 1/2" Cu pipe at the hardware store, you may notice it comes in two wall thicknesses. I was taught that the thin-walled pipe was for the cold water, and the thick-walled for the hot water. The reasoning I was given is that the Cu corrodes faster in the hot water so the thicker walls delay the eventual failure of the pipe. Often when someone installs or repairs a system they'll use the thin-walled pipe on the hot side because of its lower cost.

I've never had a corrosion failure on the cold side but I have on the hot. I've actually had more problems with the as-built cheapo Cu-plated steel wire pipe hangers. Either the pipe has vibrated within it and created a fatigue pinhole, or the plating was scraped off the hanger from the vibration and a galvanic couple was created which corroded the pipe where they touched (or both). I replaced all the hangers with dedicated plastic pipe clamps at different locations and haven't had any problems since.

Oct 21, 2014
MR166 - I'm not an expert on the chemicals, but I try to err on the side of caution. Would a good whole house or undersink water filter (thinking charcoal in there somewhere too) remove these smells and impurities? I'd hate to be unable to use my water for drinking or cooking for a year or more.

Also, any ideas on the impact on food raised in my garden? I.e., are my fruits and vegetables likely to takeup the chemicals in the water and possibly even concentrate them?

Oct 21, 2014
Delta there is an L and an M type copper pipe. M is for heating systems and L is for water systems. Fresh/drinking water systems operate at a higher pressure than heating systems thus the thicker gauge pipe.

Oct 21, 2014
As far as food raised in a garden goes I have no real idea if water from an older plastic pipe represents any sort of real/worth worrying about problem.

My guess is that you are talking about parts per billion of chemicals and that this is not really a problem .

BTW A lot of supply lines to homes in older neighborhoods are lead. This is not really a problem since they become coated over the years with inert compounds.


Oct 21, 2014
Ah plastic, the "green" lead.

Oct 21, 2014
I have a reverse osmosis filter and don't worry about chemicals in my drinking water; I also have a whole-house automatic backflush carbon filter and don't worry about chemicals in my bath or wash water, either. I had a kitty with cancer, and we needed RO-quality water for her while she was having chemotherapy. (She eventually died of the cancer, but it took five years.) The only other water I drink is from cows, beer, and fruit juices. Once you've had really pure water for a while, you'll never go back, and $1,200 for a ten-year carbon filter, and $20 a year for new RO and carbon filters, is cheap, for my health. I can't drink out of public drinking fountains any more, because I can taste the impurities and they're generally pretty nasty.

In fact, I can even taste unfiltered water in my coffee.

Oct 21, 2014
As far as food raised in a garden goes I have no real idea if water from an older plastic pipe represents any sort of real/worth worrying about problem.

My guess is that you are talking about parts per billion of chemicals and that this is not really a problem .

BTW A lot of supply lines to homes in older neighborhoods are lead. This is not really a problem since they become coated over the years with inert compounds.

My garden lines are unfiltered; the supply splits before the house entry (where my carbon filter is) and one side goes to the house, the other to the outside plumbing. I have never noticed any taste or smell of chemicals in my tomatoes or garlic, or for that matter in my sage or rosemary or lavender. I suspect the plants just don't absorb most of these chemicals.

Oct 21, 2014
Delta, in urban environments you are more likely to have your garden veggies contaminated from the soil itself. This comes from repeatedly tearing down and building houses on the site over hundreds of years (not to mention urban expansion means many of today's houses are on pre-war industrial estates).

5 years ago a school in North Sydney near me had to have their playground excavated and re-filled after testing revealed significant lead contamination from 1920s activity.

Google "garden soil contamination"...

Oct 21, 2014
Having had to replace soil taken from my backyard with fresh soil because of contamination with weed killers for years before I got here, I have to agree, animah. Not only that but watch out for supposed "organic" fertilizers that turn out to be processed chemical waste and sewage from urban areas (and not very well processed, at that).

Oct 21, 2014
Why people are worrying about simple chemicals [which have really low concentrations]? The fact that utilities add chlorine [which is pure poison] to the water supply should be your far greater concern. Contrary to popular belief, it is the green stuff (viruses, bacteria, parasitic worms) that kills people.

Oct 21, 2014
Also, please enlighten me what is up with this "organic" stuff. Do you mean if you feed plants with excrement [which contains literally all kind of nasty shit], then it is somehow safer than just fertilizing with simple nitrogen derivative chemical?

Oct 22, 2014
Tegiri: Animal waste is indeed a contaminant but unless you eat poison, the "nasty shit" is either bacteria (removed when food is washed) or properly metabolised by plants and quite safe to eat.

Plants (and animals) also absorb but are however unable to process most artificial chemicals - they simply have no evolutionary experience to make use of them. They also have no mechanism to get rid of it so it stays there - in fact in humans, a lot of the toxicity comes from bioaccumulation over time.

There's tons of research into this. Maybe start with:

http://en.wikiped...s#Humans


Oct 22, 2014
Also, please enlighten me what is up with this "organic" stuff. Do you mean if you feed plants with excrement [which contains literally all kind of nasty shit], then it is somehow safer than just fertilizing with simple nitrogen derivative chemical?

With that view, I'm guessing you hold an even lower opinion of plain old soil, which contains even nastier stuff. Anthrax, flesh eating bacteria, etc.

Nothing that says organic has to contain excrement either, as you well know.

Oct 22, 2014
Everyone is worried about chemical fertilizers in food yet we continue to increase the average lifespan by leaps and bounds. In the not too distant past few died of cancer because they did not live long enough to die from it. Inexpensive and plentiful food is of paramount importance to the survival and life span of the non wealthy. Modern agriculture and oil has been a boon to mankind.

Oct 22, 2014
...I'm guessing you hold an even lower opinion of plain old soil, which contains even nastier stuff. Anthrax, flesh eating bacteria, etc...


An article with a funny title:
http://modernfarm...ake-off/

Plants (and animals) also absorb but are however unable to process most artificial chemicals - they simply have no evolutionary experience to make use of them


So? Most of the stuff which is not digested is passed through. I'm not sure what is the context here; are we talking to significant concentrations of chemicals, e.g. people eating plastic food packaging?

Oct 22, 2014
I read the article and it is just "amazing", (not really), how cost effective solutions win out in the end. Pollyanna solutions to every day problems will eventually be displaced by true economic solutions.

Oct 22, 2014
OK, MR, you drink the contaminated water and we'll all watch to see how long before you get cancer of the >insert embarrassing body part here<.

Oct 22, 2014
Da Schneib is exactly right - Tegiri, that link I included is pretty explicit. Try eating fish you catch from a Manhattan sea wall for a year and come back to tell us about you health outcomes...

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