Technical Memorandum 

For: Bay Area Pollution Prevention Group 

Prepared by: Stephanie Hughes, P.E. 

Date: June 25, 2014 

Subject: Preliminary Comparison of PEX and Copper for Potable Water Piping 

Summary 

The wastewater community has long been interested in upstream pipe materials. In particular, 

BAPPG and member agencies have been promoting pollution prevention opportunities in the 

design and installation of copper piping systems since the late 1990s. Meanwhile, both CPVC1

and PEX2 have become options in the California plumbing code for potable water. Those actions 

initiated BAPPG members’ interest in the differences between copper and plastic pipe. To date, 

such reviews have focused primarily on the potential leaching of chemicals from the pipe 

material. While that is clearly important, I have sought to look at a wider picture, surveying 

available literature (both peer-reviewed and industry-sponsored publications) to incorporate 

installation and life cycle aspects. I have focused on PEX (rather than CPVC) in part because 

unlike other plastics, it uses brass fittings rather than epoxies, and it is being promoted in local 

hardware stores as a relatively simple do-it-yourself installation. I have assembled my findings in 

the pages that follow. In summary, my tentative findings are as follows: 

1. LIFE CYCLE: When viewed from a life-cycle perspective, PEX appears to have a lower 

global warming potential compared to copper and may have reduced impacts in other 

areas as well. 

2. WORKER HEALTH: From an installer respiratory perspective, PEX may be preferable 

to copper pipe. 

3. WATER QUALITY: PEX leaches a number of organic materials, at least within the 

initial months following installation. Copper pipe leaches copper for the initial years 

following installation. Depending on installation practices, copper pipe may also leach 

flux chemicals. Both materials may leach metals from brass fittings and fixtures. 

4. MUNICIPAL WATER DISTRIBUTION: Municipalities use PVC and HDPE as 

materials for drinking water distribution systems, providing some context for a 

discussion about consumer choice with regards to plastic pipes. 

5. CONSUMER CHOICE: A consumer’s choice of plumbing material is subjective and 

there are variety of factors that impact consumer decision-making, including health, taste 

and odor, corrosion resistance, warranty, cost, and convenience of installation. 

Please review the pages that follow for details on each of these subject areas. BAPPG may want 

to use this information to conduct additional research and/or update messages with respect to 

potable plumbing alternatives. 

 

1

 CPVC = chlorinated polyvinyl chloride, approved for potable water pipe in California in 2008. 

2

 PEX = crosslinked polyethylene, approved for potable water pipe in California in 2010. 
2 

Background 

Copper pipe corrosion has been a major concern to the wastewater community for more than a 

decade. For many years, the messages have been about proper installation and the use of a waterbased flushable flux (ASTM B813 flux); petrolatum-based, non-ASTM fluxes increase pipe 

corrosion long after the joint has been soldered. The BAPPG message is in good standing, as the 

Universal Plumbing Code (UPC) requires the use of ASTM B813 flux when installing copper 

pipe. 

The reality appears to be that there is a disconnect between standards and plumbing practices. 

While water-based flux is the standard in the UPC for potable water, the standard appears to be 

virtually universally ignored. The boots-on-the-ground plumbers and trainers appear to have 

concerns about the water-based flux, both from a workability perspective and from a health/fume 

perspective. In addition, of five plumbing stores surveyed in San Francisco, petroleum-based 

fluxes were the ONLY fluxes available in two stores.3 

These observations led to the conclusion that the vast majority of copper pipe may have been and 

may continue to be installed with the petrolatum-based flux. This led to questioning whether it is 

sufficient to provide plumbing messages only about copper pipe, given that at least one key 

pollution prevention message is ignored. This further led to a consideration of whether the 

wastewater community should understand the bigger environmental picture regarding copper 

versus plastic pipe. Therefore, this literature search has been an initial effort to try to better 

understand the life cycle, public health, worker safety and environmental impacts of these 

plumbing alternatives. 

Literature Review and Discussion 

1. Life Cycle Analyses 

Life cycle analyses (LCAs) evaluate a material or product throughout the “life” of the material. 

Such analyses can vary greatly with respect to boundary conditions and the types of impacts that 

are analyzed. For instance, the analysis might be “cradle-to-factory gate” (thus, before reaching 

the ultimate consumer) or “cradle-to-grave” (i.e., include final disposal). Such analyses might 

analyze only one metric, such as global warming potential or might evaluate multiple 

environmental metrics (such as ozone depletion and ecotoxicity). Thus, it is difficult to evaluate 

and compare life cycle analyses. 

Very few LCAs were uncovered for copper and/or PEX pipe materials. Further, typically the 

LCA was conducted for or by a particular industry (i.e. copper versus plastic) rather than 

published in a peer-reviewed application. Nevertheless, the results are intriguing and valuable to 

understand. The following papers were collected and reviewed: 

Copper LCA Only 

1. European Copper Institute, Brussels, Belgium, “The Environmental Profile of Copper 

Products,” (a summary factsheet), date not provided (obtained March 3, 2014 from 

www.copper-life-cycle.org). 

 

3

 One plumbing store staff person indicated that while they used to sell the water-based product, no one was buying 

it, so they took it off the shelves. 
3 

PEX LCA Only 

2. Carolin, S., Vanderreydt, I, et al., “THIRD PARTY REPORT: Life Cycle Assessment of 

a PEX Pipe System for hot and Cold Water in the Building,” prepared under the authority 

of The European Plastic Pipes and Fittings Association, May 2011. 

Copper and PEX LCAs 

3. Franklin Associates, Prairie Village Kansas, “Life Cycle Inventory of the Production of 

Plastic and Metal Pipes for Use in Three Piping Applications,” prepared for the Plastic 

Pipe and Fittings Association, June 2008. 

4. Geberit (multinational plumbing part manufacturer and supplier, based in Switzerland) 

“Life Cycle Assessment: Supply pipes for buildings,” January 2009 

5. Lee, Juneseok, and Easterling, Andrew, San Jose State University, “Application of the 

EIO-LCA and LCIA to Premise Plumbing Materials,” World Environmental and Water 

Resources Congress 2012, ASCE. 

The results of the five LCAs are summarized in the tables and graphics that follow. 

1. “The Environmental Profile of Copper Products,” European Copper Institute, 

Brussels, Belgium. 

Materials evaluated Only copper 

Boundary conditions Cradle-to-factory gate 

Specific Findings: 

Global warming 

potential 

900 lb CO2e / 1000 ft for 0.6 inch diameter pipe 

Conclusions “Copper mines are multi-metal mines.” Extraction and processing are 

primary impacts. Increased recovery and recycling is important, 

especially since global copper use is so large. The annual scrap available 

now equals the production rate of 20-50 years ago. 

While this copper-only study did not compare the results to PEX or 

other materials, it is useful to note that the global warming potential 

(GWP), as measured in carbon dioxide equivalents (CO2e), is within the 

range of estimates for copper in the LCA Study #3 (below). 

Funder Study provided by the European Copper Institute. 

 
4 

2. Carolin, S., Vanderreydt, I, et al., “THIRD PARTY REPORT: Life Cycle 

Assessment of a PEX Pipe System for Hot and Cold Water in the Building,” 

prepared under the authority of The European Plastic Pipes and Fittings 

Association, May 2011 

Materials evaluated PEX only, including the brass fittings 

Boundary conditions Included the extrusion, transportation, and disposal of the PEX pipe and 

brass fittings (assuming 50 years of service). Assumed that 85% of the 

material was disposed in a landfill while 15% was incinerated with 

energy recovery. Evaluated abiotic depletion, acidification, 

eutrophication, global warming, ozone depletion, and photochemical 

oxidation. 

Specific Findings: Their “functional unit” for their LCA, rather than a specific length of 

pipe, was the entire set of piping and fittings needed for a 100 m2

European apartment. This included multiple lengths and diameters of 

pipe and numerous associated fittings. Therefore, it would be 

challenging and time consuming to compare their calculations with the 

other studies. That said, below is a summary of the major contributors to 

the environmental impacts. 

Global warming 

potential 

Primary impact is from the production of the raw materials for the PEX 

pipe. The extrusion of the pipe and the production of the fittings are the 

next most important life cycle phases for global warming potential. 

Abiotic depletion Primary impact is from the production of the raw materials for the PEX 

pipe. 

Acidification Primary impact is from the production of the raw materials for the PEX 

pipe and the production of the brass fittings. 

Eutrophication Primary impact is from the production of the brass fittings. 

Ozone layer 

depletion 

Primary impact is from the production of associated plastic fittings. 

Photochemical 

oxidation 

Primary impact is from the production of the raw materials for the PEX 

pipe and associated plastic fittings. 

Conclusions End of life stage, which assumed that 85% of the material was disposed 

in a landfill while 15% was incinerated with energy recovery, was the 

least impacting life cycle phase for all the environmental impacts 

evaluated. 

Funder “Study accomplished under the authority of the European Plastic Pipes 

and Fittings Association” 

 
5 

3. “Life Cycle Inventory of the Production of Plastic and Metal Pipes for Use in Three 

Piping Applications,” Franklin Associates, Prairie Village Kansas, June 2008. 

Materials evaluated Copper, PEX, and CPVC for a 3⁄4 inch pipe for hot and cold water 

distribution 

Boundary conditions Raw material extraction through pipe fabrication and transportation 

from manufacturer to the customer. Includes manufacture and disposal 

of transportation packaging. Does not include installation, fittings, 

adhesives, or solder for pipe connections. 

Specific Findings: Copper PEX 

Global warming 

potential 

Approx. 800-1500 lb CO2e / 1000 

ft of 3/4 inch diameter pipe 

Approx. 380 lb CO2e / 1000 ft of 

3/4 inch diameter pipe 

Solid Waste 

(included process 

wastes, fuelrelated wastes, 

and postconsumer 

wastes) 

If zero recycled – NA, this analysis 

was not included.4 

If 50% recycled, approx. 200-400 

lb of waste per 1000 ft of 3/4 inch 

diameter pipe. 

If 100% recycled, approx. 50-75 lb 

of waste per 1000 ft of 3/4 inch 

diameter pipe. 

If zero is recycled, approx. 145 lb 

of waste per 1000 ft of 3/4 inch 

diameter pipe. 

If 50% recycled, approx. 80 lb of 

waste per 1000 ft of 3/4 inch 

diameter pipe. 

If 100% recycled, approx. 30 lb of 

waste per 1000 ft of 3/4 inch 

diameter pipe. 

Conclusions “The use of energy resources as raw materials for plastic resins 

increased the total energy for plastic pipe systems; however, this is more 

than offset by the heavier weight of copper pipe and the large amounts 

of energy required to produce the primary and secondary copper.” 

“Over 75 percent of the global warming potential for all pipe systems is 

from carbon dioxide from combustion of fossil fuels.” 

Funder Prepared for the Plastic Pipe and Fittings Association. 

 

 

4

 Notice the very different assumptions for recyclability of copper versus PEX. Copper is a highly valued material 

and is assumed to be far more likely to be recycled than the PEX material. 
6 

Below are two key tables pasted directly from Study #3. Copper K, L, and M refer to different 

industry standards for copper pipe, in which the thickness and weight of varies, with K being the 

thickest (and heaviest) per foot and M being the thinnest (and lightest) per foot. 
7 

4. “Life Cycle Assessment: Supply Pipes for Buildings,” by Geberit, January 2009 

Materials evaluated Copper, PEX, and other supply pipe materials 

Boundary conditions Mining to disposal (assuming incineration of PEX and recycling of 

copper), with a 50 year service life. 

Specific Findings Copper PEX 

Overall EcoIndicator Score 

(per a Dutch 

impact 

assessment 

method)5

Approx. 0.6 if 55% recycled 

Approx. 0.3 if 100% recycled 

The primary environmental 

impacts were mineral extraction 

and respiratory disease. 

<0.1 

This result was based on the 

assumption of 100% incineration 

for energy recovery (European 

analysis). As to the question of 

how the analysis would change if 

final disposal was a landfill, this is 

answered, in part by Study #2 that 

assumed 85% of the material was 

disposed in landfill and yet the 

disposal was the least impacting 

stage of the life cycle. 

The primary environmental impact 

was associated with the fossil fuel 

resource. 

Conclusions “From an ecological point of view, pure plastic drinking water pipes 

(PEX and PB6

) have the best results. Plastic-aluminum multilayer pipes 

have a slightly higher environmental impact due to the additional 

aluminum layer.” 

“The higher environmental impact of the copper and stainless steel pipes 

is due to the weight per meter, which is two to three times as high, and 

because extracting metal from metal ores is extensive and energy 

intensive” 

Funder In-house project by Gerberit, a multinational plumbing part 

manufacturer and supplier, based in Switzerland. 

 

 

5

 The Eco-Indicator Score incorporates fossil fuel resources, climate change, acidification, eutrophication, 

respiratory diseases, fossil fuel combustion, mineral extraction, ozone depletion, land use, and ecotoxicity. The 

method aggregates all the impacts into a single score. The lower the score, the lower the environmental impact. 

6

 polybutylene 
8 

Below is a key figure pasted directly from Study #4. This figure was included in Gerberit’s 

English-language summary. The full report, available in German, provides additional 

documentation and graphics. The full report also parses out each of these results into the various 

environmental impacts (i.e., fossil fuel resources, climate change, acidification, eutrophication, 

respiratory diseases, fossil fuel combustion, mineral extraction, ozone depletion, land use, and 

ecotoxicity). 

 
9 

5. Lee, Juneseok, and Easterling, Andrew, San Jose State University, “Application of 

the EIO-LCA and LCIA to Premise Plumbing Materials,” World Environmental 

and Water Resources Congress 2012, ASCE. 

Materials evaluated Copper, PEX and CPVC 

Boundary conditions Cradle to gate, not including installation, use or end-of-life disposal. 

Areas considered Considered human health, ecosystem quality, climate change and 

resources using a computer model developed by Hewlett Packard. Based 

on a follow-up discussion with the HP model developer, standard model 

assumptions were used for this analysis, which may or may not have 

been the most appropriate assumptions for these materials. 

Specific Findings Given the wide range of impacts evaluated, the figure below best 

summarizes the results. 

Conclusions “The results revealed that for all midpoint and damage impact 

categories, PEX systems have less of an impact on the environment than 

either copper or CPVC.” 

“Results... may be combined with economic, ergonomic, convenience, 

safety, and other relevant factors to produce a holistic decision model 

that can be used to optimize material selection.” 

Funder Hewlett-Packard and San Jose State University 

Below is a key figure pasted from Study #5. 
10 

2. Installer/Worker Safety 

From a worker safety perspective, soldering of copper includes the use of solder and soldering 

flux. Note that the water-flushable flux (the one required for potable water pipe and 

recommended by BAPPG agencies) has a number of organic chemicals not included in the nonflushable flux. The ingredients in two typical fluxes on the market are presented below, along 

with a couple of findings about possible health concerns. In addition, I have received anecdotal 

complaints from Bay Area plumbers regarding the water flushable flux, contending that the 

fumes are more noxious than petrolatum-based flux. 

Topic Copper PEX 

Products 

used 

during 

installation 

 Water flushable (ASTM 

B813) flux7

 Solder 

 Non-flushable (petrolatum 

based) flux8

 Solder 

PEX pipes are 

connected with 

brass fittings. 

Ingredients  Flux: 

o Ammonium chloride 

o Ethanolamine 

hydrochloride 

o Paraffic oil 

o Petroleum derivatives 

o Polyethylenepolypropylene glycol 

o Glycerine 

o Polyethylene glycol 

octylphenyl ether 

 Lead-free solder 

o Tin 

o Silver 

o Possibly antimony 

 Flux: 

o Ammonium chloride 

o Petrolatum 

o Zinc chloride 

 Lead-free solder 

o Tin 

o Silver 

o Possibly antimony 

Not applicable 

Possible 

respiratory 

concerns 

 Occupational asthma from ammonium chloride and zinc 

chloride9

 "A qualitative assessment of organic vapors released during... 

soldering of copper plumbing systems. The organic vapors 

from three soldering paste fluxes and a solder paste 

flux...included a series of aliphatic hydrocarbons, aromatic and 

polyaromatic hydrocarbons, chlorinated benzenes, oxygenated 

aromatic materials, and several chlorinated phenols."10

 Neither study evaluated the possible long-term exposure of 

heavy metals from the solder. 

Not applicable 

 

7

 Nokorode Aqua Flux MSDS 

8

 Nokorode Regular Paste Flux MSDS (a common flux found in local plumbing supply shops) 

9

 Weir, DC, Robertson, AS, Jones, S., Burge, PS, “Occupational Asthma due to Soft Corrosive Soldering Fluxes 

Containing Zinc Chloride and Ammonium Chloride,” Thorax, Vol. 44, No 3, 1989. (Reviewed abstract only.) 

10 Nikora, JA, Olson, AJ, and Steele, WC, “Identification of Organic Vapors from Commercially Available 

Soldering Fluxes During Simulated Soldering of Copper Plumbing Systems,” American Industrial Hygiene 

Association Journal, Vol 51, No. 7, pages A476-A477, 1990. (Reviewed abstract only.) 
11 

3. Water Quality / Leachants 

I have previously conducted prior reviews of leaching from plastic pipes, including discussions 

of aquatic toxicity and human health concerns.11 Below is a brief summary of likely leachants 

from copper, PEX, and CPVC. 

Leachant Copper PEX CPVC 

Chemicals 

that may 

leach 

from the 

pipe 

material 

NOTE: 

Copper 

and PEX 

include 

brass 

fittings 

and 

fixtures 

which 

leach 

copper, 

led, nickel 

and zinc.12

Copper 

Flux residual (see 

section immediately 

above) 

A number of volatile organic 

compounds may leach from 

PEX. For instance, in one study 

the following were the primary 

leachants:13

 Methyl tert-butyl ether 

(MTBE) 

 Tertiary butanol 

 4-Butoxy phenol 

 5-Methyl-2-hexanone 

In that study, there were 

additional VOCs that were 

measured and there were 

unidentified VOCs that were not 

quantified. 

In another study, the following 

were the primary leachants:14 

 MTBE 

 2,4-di-tert-butyl phenol 

A number of volatile organic 

compounds may leach from 

CPVC. The following organotins 

appear to be of most concern from 

a health standpoint: 

 Monobutyltin 

 Dibutyltin 

 Tributyltin 

A review by the AWWA 

Research Foundation suggested 

that a number of additional 

chemicals could leach from 

PVC/CPVC water systems. 15 

Some VOCs may be attributed to 

the cement solvents. Because 

CPVC formulations have changed 

over time, it is unclear whether 

these VOCs would be measured 

leaching from currently available 

CPVC pipe and associated 

solvents. 

Timescale 

of 

chemical 

leaching 

Copper will corrode 

most significantly in 

first years following 

installation (prior to a 

protective patina 

coating). It will 

continue to corrode at 

sites of turbulence, 

flux residual, or due to 

water chemistry or 

other physical/ 

chemical factors. 

In both studies referenced above, 

the concentration of MTBE was 

originally greater than the US 

EPA MCL (maximum 

contaminant level) but decreased 

with time. In the 2011 study, the 

MTBE concentration decreased 

below this value in 5 months. 

That study concluded that the 

overall potential health concern 

was low, but that the odor could 

negatively affect drinking water 

for up to one year. 

Based on available evidence, it 

appears that organotins are 

released from CPVC pipe and 

may do so for a number of days 

under typical use conditions. It is 

unclear the length of time over 

which this leaching would 

continue in a residential setting.16 

 

11 Hughes, Stephanie, “CPVC for Potable Water Piping: Review of Chemical Leaching Data and Related Toxicity 

Information” technical memorandum to the PARWQCP, September 2008. 12 Kimbrough, David, “Source Identification of Copper, Lead, Nickel and Zinc Loading in Wastewater Reclamation 

Plant Influents From Corrosion of Brass in Plumbing Fixtures,” Environmental Pollution, Vol 157, 2009. 

13 Skjevrak, I., et al, Volatile Organic Compounds Migrating from Plastic Pipes (HDPE, PEX, and PVC) Into 

Drinking Water, Water Research (2003) 1912-1920.

14 Lund, V, et al., “Long Term Study of Migration of Volatile Organic Compounds from Cross-linked Polyethylene 

(PEX) Pipes and Effects on Drinking Water Quality,” Journal of Water and Health, Volume 9, 2011. 

15 Tomboulian, P., Schweitzer, L., Mullin, K., Wilson, J., & Khiari, D. (2004). Materials used in drinking water 

distribution systems: contribution to taste and odor. Water Science and Technology , 219-226. 16 Hughes, Stephanie, “CPVC for Potable Water Piping: Review of Chemical Leaching Data and Related Toxicity 

Information” technical memorandum to the PARWQCP, September 2008. 
12 

4. Municipal Water Supply Material Choices 

According to California regulations, PVC and HDPE are among the materials that may be used 

for drinking water mains. The table below was pasted from “California Regulations Related 

to Drinking Water” as of July 1, 2103.

17 While PEX is not on the list, the use of other plastics 

throughout water distribution systems does provide a context with which to consider consumer 

pipe choices. 

5. Consumer Choice 

Dr. Juneseok Lee, a professor at San Jose State University (and author of Study #5) has been 

reviewing consumer decision making with regard to plumbing materials. He has estimated that in 

the USA, about 90% of home plumbing systems are copper pipe, and that pinhole leaks have 

become a concern due to property damage, property values, and insurance concerns.18 He studies 

consumer preferences and decisions, and in particular has conducted surveys in a region prone to 

pinhole leaks in copper pipe. While surveyed homeowners indicated that health, taste, and odor 

were dominant considerations, they sometimes stated preferences to a survey that differed from 

their real-life choices. On the following page are a table and two pie charts pasted from Dr. 

Lee’s research, summarizing parameters that impact consumer choice and the plumbing 

selections made by households that replumbed their homes.19 Dr. Lee concluded that “the 

choice of plumbing materials is inevitably subjective and, in real life, numerous factors influence 

the selection of a particular pipe material.” 

 

17 Available from www.cdph.ca.gov. 18 Lee, et al., “Case Study: Preference Trade-Offs Toward Home Plumbing Attributes and Materials,” Journal of 

Water Resources Planning and Management, ASCE, July/August 2009. 

19 Lee et al., “Homeowners’ decision-making in a premise plumbing failure prone area,” Journal AWWA, Vol 

105:5, May 2013. 
13 

The following figures are directly from: Lee et al., “Homeowners’ decision-making in a 

premise plumbing failure prone area,” Journal AWWA, Vol 105:5, May 2013. NOTE: the 

surveyed community was in a region that was prone to pinhole leaks in copper pipe. 

Endnotes 

This concludes the summary of my initial findings. BAPPG may want to use this information to 

conduct follow-up analysis and/or to update messages with respect to potable plumbing 

alternatives. I intend to summarize this information at the August 2014 BAPPG meeting to 

initiate a discussion about next steps, if any.