**2. Literature review**

As mentioned above, the household decision-making process with regards to choosing a plumbing material for a private residency is complicated, and involves several factors, such as federal, state, and local standards and regulations, corrosion risk perceptions of drinking water as viewed by infrastructure service providers, insurance companies, households, as well as the financial impact of corrosion prevention. The regulations and standards of the federal, state, and local governments have major impacts on the plumbing material chosen for installation in a private house. These regulations influence the services provided by plumbers, home builders, material producers, and water utility companies (Lee et al., 2009).

The public perceptions of corrosion risk and cost of prevention play a fundamental role in consumers' drinking water decisions. Homeowners' perceptions of risk and cost of prevention may affect households' decisions on plumbing material repairs and replacement, as well as the type of material used. When informed about the attributes of each plumbing material alternative, consumers can decide on the most preferred plumbing system. The decision of choosing an appropriate plumbing material is based on various plumbing material attributes, such as cost (material cost plus labor and installation cost), health effects, corrosion susceptibility, strength, property real estate values, and behavior in the case of a

As it is important to learn household perceptions and preferences for drinking water infrastructure, the chapter objective is to investigate homeowners' preferences for plumbing materials (i.e. copper, plastic, an epoxy coating), as well as preventive techniques against corrosion based on households' experiences with plumbing material failures. In 2007, a survey of a Southeastern Community in the United States was conducted in order to meet these goals, and obtain information on the prevalence of plumbing material failures, householders' experiences with plumbing material failures, the cost of repairs and property damages due to the material failures, and household preferences for plumbing systems.

The objective of the study is fulfilled by analyzing in-depth the information of the prevalence of home plumbing corrosion, preventive measures taken against corrosion, as well as the financial, health, and time costs associated with repairing faulty plumbing systems. In addition, analyses are performed to elicit household preferences for plumbing materials, and to identify the attributes important to choosing home plumbing systems. Summary statistics as well as regression methods, such the Ordered Logit model, are employed to support the study, and provide insight into the scale of corrosion in the community, the financial burden accrued from repairing the problem, and finally

The knowledge gained from this chapter can be helpful in the design of public policy aimed at corrosion prevention. The research provides information to federal and state officials, plumbers, plumbing material manufacturers, and utility company managers on the financial burden individual households are willing to take on to avoid corrosion. In addition, the study should help in bridging the gap between the perceptions of the public and drinking water infrastructure experts, regarding the problem of pinhole leaks and other corrosion

As mentioned above, the household decision-making process with regards to choosing a plumbing material for a private residency is complicated, and involves several factors, such as federal, state, and local standards and regulations, corrosion risk perceptions of drinking water as viewed by infrastructure service providers, insurance companies, households, as well as the financial impact of corrosion prevention. The regulations and standards of the federal, state, and local governments have major impacts on the plumbing material chosen for installation in a private house. These regulations influence the services provided by plumbers, home builders, material producers, and water utility

recommendation for the best plumbing materials for household use.

fire (Champ et al., 2003).

related issues.

**2. Literature review** 

companies (Lee et al., 2009).

To make an informed decision about the optimal plumbing material for their home, homeowners need information on the various risks involved in choosing plumbing systems. When informed about the plumbing material characteristics, the consumers are able to decide on an alternative most preferable to them based on the preference trade-offs among plumbing materials' attributes. Households make decisions on a plumbing alternative when either replacing an existing system or installing a plumbing system in a new house. Each alternative has advantages and disadvantages that impact health and the overall cost of installation and maintenance. The problem becomes more complex as consumers think in terms of cost (material plus labor charges), taste and odor of the water, corrosion problem, longevity of the pipe system, fire retardance, convenience of installation or replacement, plumbers' and general contractors' opinions or expertise, and proven record in the market. Householders weigh each of these attributes in order to choose the most preferred option for their houses (Lee et al., 2009).

For example, Lee et al. (2005), utilizing the AHP method, studied the preferences for plumbing materials of Virginia Tech potable water experts. Participants ranked the health effects, reliability, taste and odor, and longevity as the most important attributes when choosing a plumbing material. Property value and fire resistance were listed at the bottom of the ranking. These results showed that health, water taste and odor dominate preferences for plumbing materials. Lack of reliability resulting in the need to repair the damage associated with pipe corrosion relates to stress and a worry about future leaks (Lee et al., 2005).

There are several plumbing material types for a householder to choose from when deciding on a plumbing material to be installed in a house: copper, plastic (CPVC and PEX), and stainless steel. According to Marshutz' survey (2000), copper is used in nearly 90% of homes in the U.S. followed by PEX (cross linked polyethylene) with a 7% installation rate, and CPVC (chlorinated polyvinyl chloride) with a 2% installation rate. Telephone surveys of plumbers conducted in 2005 show an increased use of plastic pipes, due to easier handling in installation and lower material cost (Scardina et al., 2007).

Copper is the most widely used material in residential plumbing and has several advantages, including affordability, fire resistance, few health hazards, and durability. Woodson (1999) studied the performance of different plumbing material alternatives: copper, CPVC, and PEX. He found copper pipes generally perform well, except for cases involving major leak problems (Woodson, 1999). Due to increased pinhole leak incidents reported in hotspot areas of the U.S. (eg. Washington, D.C. suburbs and Sarasota, Florida), many consumers replaced copper with other options. Concerns with copper pipes include a metallic taste, especially with long stagnation periods and increased absorption of residual disinfectant by the pipe walls. High levels of copper can cause nausea, vomiting, and diarrhea (ATSDR, 2004). Elevated copper levels in drinking water may increase lead levels when lead solder joints, lead service lines, or brass fixtures are present in plumbing material. It is advised to test for lead when testing for copper levels in drinking water as lead and copper enter drinking water under similar conditions (Lee, 2008).

PEX (polyethylene cross linked) is another type of plumbing material often used in residential plumbing. This material is used to make flexible plastic pipes. A different plumbing design characterized by individual pipe lengths is required for every fixture. The

Households' Preferences for Plumbing Materials 425

parts of the U.S., such as Florida and California. They found 47% of all respondents willing to pay a positive amount to ensure that material would remain leak-free, 27% unwilling to pay any amount to ensure that material would remain leak-free, and 25% unsure about how much they would be willing to pay. About 6% of respondents were willing to pay at least \$4,000 to ensure that material would remain leak free for 50 years. This amount is 10 times the suggested base material cost for re-plumbing a 2,000 square foot house. The mean willingness-to-pay estimate was higher for respondents with leaks compared to respondents who had no leaks, constituting \$1,130 and \$1,007 respectively. Finally, 45% of respondents with leaks and 41% of respondents without leaks were not willing to pay for leak-free

The Southeastern Community located in the United States of America was established in 1980s, and spans over 4,700 acres. There are about 3,300 homes, including condos and apartments, with 6,600 residents in total. Most of the resident population is retired, so the community is rather a homogenous group. The first incidents of pinhole leaks were reported

In August 2007, a questionnaire was sent to 1600 households in the Southeastern Community. The community's Property Owners' Association provided a list of the residents' names and addresses, and the sample was randomly selected from this list. Members of the Assocaition's Board reviewed the survey questions. The Association encouraged participation of community residents in the study. The survey was distributed following the Dillman technique of mail surveying, which included mailing a questionnaire with postage-paid return envelope, sending a reminder card, and mailing a second copy of

In 2007, two surveys were conducted by the Virginia Tech researchers to learn about the home plumbing issues and the preventive measures taken against future corrosion incidences. The first survey acquired information on the incidents of pinhole leaks in the residential area, the adoption rate of preventive measures against corrosion, the homeowners' preferences for corrosion risk, and the costs associated with a leak free environment. The second survey elicited preferences for three hypothetical plumbing materials with different attribute levels. The sample of respondents was based on the first Southeastern Community survey respondents, who were willing to participate in the

A follow-up survey was administered in October 2007 to learn household preferences for home plumbing materials. The follow-up survey was sent 363 Southeastern Community householders who responded to the first survey, and who agreed to participate in future surveys. The respondents were exposed to attributes of three hypothetical to them plumbing system materials, which were left unnamed to avoid a survey exposure bias2. The materials represented in the questionnaire were copper, plastic, and epoxy coating. Materials were left unnamed, because most homeowners were familiar with at least one material type (copper,

2 Survey Exposure Bias represents the ability to skew respondents' responses, based on the information

either presented during the study or known prior to the study (Champ et al., 2003).

plumbing materials (Dietrich et al., 2006; Kleczyk et al., 2006; Scardina et al. 2007).

**3. Survey design and distribution** 

the survey to nonresponders (Dillman, 1978).

follow-up questionnaire.

in 2001.

main advantage of PEX is the lack of joints requiring soldering, which decreases the probability of pipe failures. On the other hand, PEX plumbing has raised some concerns regarding possible leaching of MTBE (methyl tertiary butyl ether), ETBE (Ethyl tert-butyl ether), and benzene into drinking water. Other concerns are the negative health impacts associated with PEX's reaction with chlorine, increased water odors (Durand & Dietrich, 2007), the material's ability to withstand fire, and its final disposal (PRNews Wire, 2004). In addition, PEX may become stiff in cold weather, which makes faulty pipe repairs more difficult. PEX use has been approved in all U.S. states (Toolbase News, 2008), and has met all health standards set by NSF/ANSI-61 for potable water supply (NSF, 2008).

CPVC plumbing material is also employed in residential plumbing, but presents many concerns. For example, it can become brittle when exposed to sunlight for an extended period of time, and presents possible negative health effects from microbial growth in the inner pipe. Other possible concerns are cracking in the event of an earthquake, plastic water taste, and melting in the event of fire. The solvents used to join fittings and pipe lengths may contain volatile organic compounds (VOCs), requiring proper ventilation during installation, and causing unpleasant odor problems. However, CPVC by itself has a low odor potential (Heim & Dietrich, 2007).

The last plumbing material type is stainless steel, which is often used in industrial applications. Stainless steel provides excellent resistance to corrosion, due to the presence of 18% chromium and 8% nickel (Roberge, 2000). The stainless steel material is, however, expensive. Due to the cost, its use is limited to specialized industries for conveying chemicals or other similar applications (Lee, 2008). A concern with stainless steel pipes is the possibility of leaching chromium into drinking water; however, all U.S. states have approved stainless steel use (NSF, 2008; Roberge, 2000).

The economically sustainable optimal replacement time for home plumbing systems is about 22 years after installation (Loganathan & Lee, 2005). The estimate, however, is dependent on the source and type of the employed data (Loganathan and & Lee, 2005). When it is time to replace the plumbing system, the homeowners have to decide on a plumbing system to be installed in their homes. For example, several homeowners in a Southeastern Community in the U.S. replaced their copper pipes with PEX. According to them, PEX is less labor intensive in case of installation, resistant against corrosion, and less expensive compared to copper (Plumbing and Mechanical Magazine, 2007).

However, plumbing material replacement or repairs can be rather expensive. Farooqi and Lee (2005) conducted a survey of plumbers in the U.S. and found plumbers to charge their work on an hourly basis. The cost per hour varied from \$45 to \$75, and the total cost of plumbing material replacement ranged from \$3,654 for PEX to \$5,680 for copper pipes (Farooqi & Lee, 2005). Furthermore, fixing dry wall, floor tiles, or ceilings affected by plumbing material replacement is not part of the services provided by the plumber, and homeowners have to hire a general contractor to fix the water related damage. Kleczyk and Bosch (2008) have reported the additional costs associated with damage from pipe failures reaching as much as \$25,000, and forcing household members to reside in temporary housing during the repair period.

On the other hand, Scardina et al. (2007) (also discussed in Kleczyk et al. 2006) investigated the willingness-to-pay for a leak-free plumbing material in households located in different

main advantage of PEX is the lack of joints requiring soldering, which decreases the probability of pipe failures. On the other hand, PEX plumbing has raised some concerns regarding possible leaching of MTBE (methyl tertiary butyl ether), ETBE (Ethyl tert-butyl ether), and benzene into drinking water. Other concerns are the negative health impacts associated with PEX's reaction with chlorine, increased water odors (Durand & Dietrich, 2007), the material's ability to withstand fire, and its final disposal (PRNews Wire, 2004). In addition, PEX may become stiff in cold weather, which makes faulty pipe repairs more difficult. PEX use has been approved in all U.S. states (Toolbase News, 2008), and has met all

CPVC plumbing material is also employed in residential plumbing, but presents many concerns. For example, it can become brittle when exposed to sunlight for an extended period of time, and presents possible negative health effects from microbial growth in the inner pipe. Other possible concerns are cracking in the event of an earthquake, plastic water taste, and melting in the event of fire. The solvents used to join fittings and pipe lengths may contain volatile organic compounds (VOCs), requiring proper ventilation during installation, and causing unpleasant odor problems. However, CPVC by itself has a low

The last plumbing material type is stainless steel, which is often used in industrial applications. Stainless steel provides excellent resistance to corrosion, due to the presence of 18% chromium and 8% nickel (Roberge, 2000). The stainless steel material is, however, expensive. Due to the cost, its use is limited to specialized industries for conveying chemicals or other similar applications (Lee, 2008). A concern with stainless steel pipes is the possibility of leaching chromium into drinking water; however, all U.S. states have

The economically sustainable optimal replacement time for home plumbing systems is about 22 years after installation (Loganathan & Lee, 2005). The estimate, however, is dependent on the source and type of the employed data (Loganathan and & Lee, 2005). When it is time to replace the plumbing system, the homeowners have to decide on a plumbing system to be installed in their homes. For example, several homeowners in a Southeastern Community in the U.S. replaced their copper pipes with PEX. According to them, PEX is less labor intensive in case of installation, resistant against corrosion, and less

However, plumbing material replacement or repairs can be rather expensive. Farooqi and Lee (2005) conducted a survey of plumbers in the U.S. and found plumbers to charge their work on an hourly basis. The cost per hour varied from \$45 to \$75, and the total cost of plumbing material replacement ranged from \$3,654 for PEX to \$5,680 for copper pipes (Farooqi & Lee, 2005). Furthermore, fixing dry wall, floor tiles, or ceilings affected by plumbing material replacement is not part of the services provided by the plumber, and homeowners have to hire a general contractor to fix the water related damage. Kleczyk and Bosch (2008) have reported the additional costs associated with damage from pipe failures reaching as much as \$25,000, and forcing household members to reside in temporary

On the other hand, Scardina et al. (2007) (also discussed in Kleczyk et al. 2006) investigated the willingness-to-pay for a leak-free plumbing material in households located in different

expensive compared to copper (Plumbing and Mechanical Magazine, 2007).

health standards set by NSF/ANSI-61 for potable water supply (NSF, 2008).

odor potential (Heim & Dietrich, 2007).

housing during the repair period.

approved stainless steel use (NSF, 2008; Roberge, 2000).

parts of the U.S., such as Florida and California. They found 47% of all respondents willing to pay a positive amount to ensure that material would remain leak-free, 27% unwilling to pay any amount to ensure that material would remain leak-free, and 25% unsure about how much they would be willing to pay. About 6% of respondents were willing to pay at least \$4,000 to ensure that material would remain leak free for 50 years. This amount is 10 times the suggested base material cost for re-plumbing a 2,000 square foot house. The mean willingness-to-pay estimate was higher for respondents with leaks compared to respondents who had no leaks, constituting \$1,130 and \$1,007 respectively. Finally, 45% of respondents with leaks and 41% of respondents without leaks were not willing to pay for leak-free plumbing materials (Dietrich et al., 2006; Kleczyk et al., 2006; Scardina et al. 2007).
