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Journal of Environmental Management 128 (2013) 683e689

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Journal of Environmental Management

journal homepage: www.elsevier .com/locate/ jenvman

Water conservation quantities vs customer opinion and satisfactionwith water efficient appliances in Miami, Florida

Mengshan Lee*, Berrin TanselCivil and Environmental Engineering Department, Florida International University, 10555 W. Flagler St., Miami, FL 33174, USA

a r t i c l e i n f o

Article history:Received 26 November 2012Received in revised form14 May 2013Accepted 23 May 2013Available online 10 July 2013

Keywords:SustainabilityWater conservationWater use behaviorWater use efficiency measuresResidential customersSynergistic effect

* Corresponding author. Tel.: þ886 423590121x300E-mail addresses: mlee011@fiu.edu, mengshanlee@

0301-4797/$ e see front matter � 2013 Elsevier Ltd.http://dx.doi.org/10.1016/j.jenvman.2013.05.044

a b s t r a c t

During 2006e2007, Miami-Dade County, Florida, USA, provided incentives for low income and seniorresidents in single family homes for retrofitting with high efficiency fixtures. The participating residenceswere retrofitted with high-efficiency toilets, showerheads, and aerators. In 2012, a telephone survey wasconducted to evaluate the satisfaction of the participants and the associated effects on water conser-vation practices. This study evaluates the attitudes and opinions of the participants relative to water useefficiency measures and the actual reduction in water consumption characteristics of the participatinghouseholds. The participant characteristics were analyzed to identify correlations between the socio-demographic factors, program satisfaction and actual water savings. Approximately 65.5% of the sur-vey respondents reported changes in their water use habits and 76.6% reported noticeable reduction intheir water bills. The analyses showed that the satisfaction levels of the participants were closelycorrelated with the actual water savings. The results also showed that satisfaction level along with watersaving potential (i.e., implementation of water efficiency devices) or change of water use habits hasprovided positive synergistic effect on actual water savings. The majority of the participants surveyed(81.3e89.1%) reported positive attitudes for water conservation incentive program and the benefits of thehigh efficiency fixtures.

� 2013 Elsevier Ltd. All rights reserved.

1. Introduction

Water conservation is recognized as a critical factor for waterdemand management (Baumann et al., 1998). The water demandmanagement strategies can be broadly divided into three majorcategories as economic, technological and behavioral (Brooks,2006; Saurií, 2003). Demand management strategies such as wa-ter metering, rebate/retrofit programs for high efficiency devices,water efficiency labeling, water conservation or education pro-grams, and leakage control have been proposed and/or imple-mented for various applications (Inman and Jeffrey, 2006).Recently, the water demand management focus has shifted toresidential customers by implementation of programs that aredesigned to encourage voluntary water conservation either byaltering water use behaviors or utilizing water use efficiency fix-tures (Lee and Tansel, 2012; Lee et al., 2011a; Syme et al., 2000).

Residential households are considered to have the potential forsignificant water and energy savings (Willis et al., 2010). The U.S.EPA and Federal Energy Management Program (FEMP) identified

45/39; fax: þ886 423594276.thu.edu.tw (M. Lee).

All rights reserved.

water efficiency Best Management Practices (BMPs) for indoorwater use fixtures such as toilets, showerheads andwashers (Mayeret al., 1999; Vickers, 2001). The strategies for promoting use ofwater efficiency fixtures have been successful in some communitiesresulting in up to 35% of indoor water savings (Balbin et al., 2010;Inman and Jeffrey, 2006; Lee et al., 2011b; Mayer et al., 2004).Recent studies have reported that water conservation behaviorsmay pose significant influence on water conservation quantities(Gilg and Barr, 2006; Kolokytha et al., 2002; Millock and Nauges,2010; Randolph and Troy, 2008; Russell and Fielding, 2010).

Water conservation behaviors can be divided into two majorcategories as (1) efficiency behaviors, and (2) curtailment behaviors(Gardner and Stern, 1996). Efficiency and curtailment behaviorsrefer to on-off behaviors (i.e., installing high efficiency fixtures) andconservation actions (i.e., reducing time for showering), respec-tively. Stern (2000) reported that the major causes of water con-servation behaviors as attitudes, beliefs, habits or routines,personal capabilities and contextual force. Russell and Fielding(2010) observed that committed water conservation behavior wasconsistent with the theory of planned behavior that user usuallyposed positive attitudes to water conservation, perceived socialsupport (i.e., personal norms) and behavioral control. Socio-demographic characteristics, on the other hand, are usually

M. Lee, B. Tansel / Journal of Environmental Management 128 (2013) 683e689684

considered as proxies for personal capabilities (such as knowledgeand skills) or contextual factors (physical infrastructure and tech-nical facilities in the household) in facilitating water conservationbehaviors (Stern, 2000). Socio-demographic and psychologicaldeterminants are expected to provide an essential basis for exam-ining the nature of water conservation behaviors. There is a need ofexploring the interrelationships between social and psychologicalvariables and water conservation (Campbell et al., 2004).

During 2006e2007, Miami-Dade County, Florida invited lowincome seniors and other qualifying low income residents in singlefamily homes built before 1996 to participate in the High EfficiencyFixture Retrofit Program. The participating residences were retro-fitted (free of charge) with up to two high-efficiency toilets, up totwo high efficiency showerheads, a maximum of two bathroomfaucet aerators, and a kitchen faucet aerator. The expected watersavings, as detailed in Table 1, for the installed high efficiencyshowerhead, aerator and toilet were 28, 9.3 and 34.7 gallons perhousehold per day (GPHD), respectively (Lee et al., 2011b; Mayeret al., 2004). The purpose of this study was to assess the waterconservation quantities and associated effects (e.g. satisfactionlevel and change of water use habits) of the participating customersin the High Efficiency Fixture Retrofit Program. A telephone surveywas used to collect feedback from the participants. The survey re-sults were analyzed to identify the correlations between the waterconservation quantities, changes in habits and satisfaction levels ofthe participating costumers.

2. Methodology

2.1. Sample description

The High Efficiency Fixture Retrofit Programwas first started inlate 2006 with total of 271 senior or low income households withaverage 2.3 occupants in the households. These participants areliving in houses with characteristics of average 2.7 bedrooms, 1.5bathrooms and adjusted building footage of 130 m2 (Lee et al.,2013). In urban area of Miami-Dade County with total populationof about 2.59 million people (estimated in 2012), approximately14.2% of the total population is seniors (persons who are over 65years old) and 17.9% of the total population is persons belowpoverty level from 2007 to 2011. The average number of occupantsin a household in Miami-Dade County from 2007 to 2011 is 2.93people (U.S. Census Bureau, 2013).

Household water demand reduction for High Efficiency FixtureRetrofit Program participants ranges from 18.8% (for survey par-ticipants) to 23.8% (for all participants) within three years ofimplementation, whereas the reduction for customers participatein other high efficiency appliances rebate programs is only

Table 1Description of high efficiency fixtures used in the senior and low income full retrofitprogram.

Fixtures Water userate

Water savingpotential(GPHDa)

Installedfixtures(unit/household)

Maximumnumber offixture installed(unit/household)

Toilet 1.28 GPFb 34.7d 1.4 2.0Showerhead 1.5 GPMc 28.0d 1.4 2.0Aerator 1.5 GPMc 9.3e 2.0 3.0f

a GPHD: gallons per household per day.b GPF: gallons per flush.c GPM: gallons per minute.d Lee et al. (2011b).e Mayer et al. (2004).f 2 for restrooms and 1 for kitchen.

approximately 14.5% (Table 2). This can be partly due to the dif-ferences in family composition, life style, and the quantity of watersaving devices installed (Lee et al., 2013). The declining trends inhousehold water demand for all program participants demon-strated the success of implementation of water conservationpractices.

2.2. Survey procedure

The survey participants were randomly selected from theparticipating households in the High Efficiency Fixture RetrofitProgram (n ¼ 271) since the first year of the project implementa-tion in fiscal year 2006e2007. Stratified random sampling methodwas applied in selecting survey participants for representing thetotal population. The survey group was first ranked by their waterconsumption data (from highest to lowest) and divided into sub-groups with different water consumption ranges to ensure thatparticipants with different water consumption characteristics areincluded in the survey. In total, 121 participating households wereselected for the survey. The survey was conducted by telephoneusing a questionnaire. The questionnaire included questions in thefollowing four categories:

1. Water-using-related socio-demographic characteristics (i.e.,address, gender, number of occupants in household, educationlevels of occupants, verification of the number and type ofwater use efficiency fixtures still in place at the residence);

2. Customer satisfaction (i.e., ease of application process, sched-uling of appointment, installation process, and use of product);

3. Effects of the project (i.e., change of water use habits, monetarysavings on water bill, recommendations to others on watersaving devices, and, interest in trying new water saving de-vices); and

4. Awareness of the program (i.e., obtained information fromtelevision or radio, awareness of other water conservationprograms from MDWASD, and, knowledge of water conserva-tion programs from other organizations).

The survey results were recorded and entered into an excelformat for further analysis. Full responses were received from 64households surveyed out of 121 attempted, which corresponds to52.8% response rate.

2.3. Data analyses

The potential water savings in relation to the number of highefficiency fixtures installed in the participating households wereevaluated using an index based water saving potential. The watersaving potential of each household was evaluated on a scale of 1e3.As shown in Table 3, the customers with water saving potentialindex of 3 had amaximum of two high efficiency showerheads, twohigh efficiency toilets and three high efficiency aerators. A

Table 2Household water demand changes of surveyed participants in comparison withother program participants within the community.

Participants (mean, GPHDa) Base year 1st year 2nd year 3rd year

Survey participants (n ¼ 64) 198.7 188.2 191.5 161.3HEFRP average (n ¼ 271)b 203.9 197.4 184.9 155.3REBATEs average (n ¼ 1829)c 259.5 248.9 231.3 222.0

a GPHD stands for gallons per household per day.b High efficiency fixture retrofit program (same as SLIFR program in Lee et al.,

2013).c Customers participated in either toilet, showerhead or clothes washer rebate

programs (Lee et al., 2011a, b).

Table 3Socio-demographic characteristics of the survey sample.

Characteristics Type %

Gender Male 46.9Female 53.1

Family sizea Single occupant 21.92e3 occupants 68.8More than 3 occupants 6.3

Family composition Senior (>65) 68.8Adult (between 18 and 65) 26.4Child (<18) 5.0

Type of family Senior family 82.8Low income familyb 7.8

Education level Graduate degree 1.6College 29.7High school 42.2Less than high school 23.4

Water saving potential index 1 (�72 GPHDc) 18.82 (72e144 GPHDc) 64.13 (>144 GPHDc) 17.2

a The average number of occupants for the program participants and the Miami-Dade county are 2.3 and 2.93 people, respectively.

b Based on the tax exemption.c GPHD stands for gallons per household per day.

Table 4Socio-demographic characteristics, satisfaction level and associated effects of theprogram in relation to perceive savings in water bill.

Characteristics c2 pa

Socio-demographic Gender 0.71 0.700Family size 3.57 0.467Family composition 2.57 0.631Tax exemption 0.65 0.722Education level 10.08 0.121Water saving potentialindex

3.03 0.553

Satisfaction level Product satisfaction 13.31 0.038Customer satisfactionduring service installation

15.47 0.017

Associated effectsof the program

Change of water use habits 24.91 <0.001Interested in trying newwater savings devices

16.76 0.002

Recommended this programto others

6.27 0.043

a For chi-squared probability of greater than or equal to 0.05 indicates that thetwo parameters are statistically independent. For detail information please refer toTable 1 and 2 in supplementary materials.

M. Lee, B. Tansel / Journal of Environmental Management 128 (2013) 683e689 685

household with a water saving index of 1 corresponds to watersaving potential of 72 GPHD.

The water use data and actual water savings of the participantswere obtained from the water consumption data during 2007 and2010 from the customer billing database. Chi-square independencetests were conducted and correlation coefficients were calculatedto determine the significant differences and identify correlationsbetween the parameters studied. Synergy index was also con-ducted for determining the synergistic interaction effect betweendeterminants. The statistical calculations were conducted by S-plusstatistical software (TIBCO Software Inc, Palo Alto, CA).

3. Results and discussion

3.1. Socio-demographic characteristics

Socio-demographic characteristics of the survey participants areprovided in Table 3. Majority of the individuals surveyed were fe-male (seniors) with a household size of 2e3 occupants and watersaving potential index of 2 or 3 (i.e., with more than 2 of each typeof high efficiency fixtures). Majority of the participants had highschool degrees (42.2%) followed by college and less than highschool degrees. These participants also have household character-istics of adjusted building footage of 1471 ft2, average 2.6 bedroomsand 1.5 bathrooms (not shown in Table 3). The socio-demographiccharacteristics of the participants were analyzed in relation to theresponses during the survey for observing savings in the water billto identify correlations between the determinants (Table 4 andTable 1 in supplementary material). About 76.6% of the participantshave noticed savings in their water bill, while 9.4% and 14% of therespondents did not notice or were uncertain of the water savings,respectively. Based on the results from Table 4, it can be concludedthat all of the studied socio-demographic characteristics are inde-pendent of the observation of savings in the water bill.

Family composition is considered as a possible factor in affectingwater conservation. For this study, since the participating house-holds were seniors, interpretation of the correlations between thedeterminants may be limited. The findings based on the selectpopulation of seniors and low income families may not be repre-sentative of the community as a whole. No significant correlationwas observed between gender and the perceived water savings.This can be partially due to the insignificant differences within the

surveyed group as well as the similar environmental beliefs be-tween males and females (Corral-Verdugo et al., 2003). This resultis different from the statement that women usually invest moretime than man inwater consuming activities (Corral-Verdugo et al.,2003). The average number of occupants in the participatinghouseholds is 2.2 persons, which is consistent with the result that90.7% (Table 3) of the participants have less than or equal to 3persons in the family. As shown in Table 4, there is no significantrelation between the family size and the observation of savings onthe water bill, which is different from Gilg and Barr (2006)concluded smaller households with fewer residents were oftenenvironmentalists and would be more likely to practice waterconservation behaviors. Among all the participating households,82.8% were senior families and the rest were low income families,and, approximately 91% of the participants were either adults orseniors. With the limitation of this study, it is not applicable torelate age as a determinant for water savings. Therefore, there wasno sufficient evidence to prove that age has significant impacts onperceiving water savings. Corral-Verdugo et al. (2003) stated thatolder people are most likely to develop more utilitarian water be-liefs than that in younger people, which suggests that adults wouldinvest more time in water consuming activities than youngerpeople.

The education level of the residents had no significant impact onobserving water savings (Table 4), while majority of the partici-pants were seniors and only a small percentage (31.3%) of them hadformal education beyond the high school. This result is similar tothe findings reported by other studies (Hurd, 2006; Millock andNauges, 2010) that people with high levels of education are notnecessarily pro-environmental. Participating households with wa-ter saving potential index of 1, 2 and 3 were 18.8%, 64.1% and 17.2%,respectively. No significant correlation was observed between thewater saving potential index and the perceived savings in the waterbill based on the results from Chi-square test (Table 4). And, sig-nificant correlation between the water saving potential index andthe changes in water use habits was presented (Table 5). Theinsignificant correlation between water saving potential index andperceiving water savings can be validated as shown in Table 6.Participants with water saving potential index of 3 posed a verywide range of household water savings (from �9.49 to 31.1 GPHD),whereas participants with water saving potential index of 1 and 2perceived positive values in household water savings (for confi-dence interval at 95% confidence level excluding outliers). Thisfinding suggests that implementation of water conservation

Table 5Correlation coefficients for characteristics and responses of the survey participants.

Correlation coefficienta Water savingpotential

Scheduling ofappointment

Service duringinstallation

Productsatisfaction

Changein wateruse habits

Perceive savingsin water bill

Scheduling of appointment 0.50 0.59Service during installation 0.50 0.70Product satisfaction 0.59 0.70Changes in water use habits 0.25 0.55Perceive savings in water bill 0.55

a Blod numbers are at significant level of 0.01 and the rest are at significant level of 0.05. A higher number of correlation coefficient indicates stronger the correlation.

80

100Ease of application processScheduling of appointmentCustomer service during installation

M. Lee, B. Tansel / Journal of Environmental Management 128 (2013) 683e689686

appliances may not be the key factor affecting the level of actualwater savings, however, this argument may not be representativefor the community or the water conservation program as whole, asother water-related determinants may also contribute to thehousehold water savings in many ways.

3.2. Customer satisfaction and actual water savings

The responses for the customer satisfaction relative to thedifferent aspects of the program are presented in Fig. 1. Between 81and 89% of the respondents were very satisfied with the program. Asignificant number of participants were satisfied with the ease ofapplication and the scheduling of the installation appointment(81.3% and 85.9%, respectively). Higher level satisfaction wasobserved relative to the customer service during installation andproduct satisfaction (86.1% and 89.1%, respectively).

The highest positive correlation coefficient among all the de-terminants was between the satisfaction during installation andproduct satisfaction (Table 5). High correlation coefficients werealso observed between the scheduling of appointment and serviceduring installation, as well as between scheduling of appointmentand product satisfaction. These findings imply that satisfactionwiththe installation process directly impacted the satisfaction with theuse of the product. Customers’ satisfaction level was correlatedwith the observation of water savings and changes in water usehabits. As presented in Tables 4 and 7, the correlations were sig-nificant between (1) the product satisfaction and observation ofsavings on the water bill, and (2) the customer satisfaction duringservice installation and observation of savings on the water bill.

Positive attitudes on product satisfaction level have contributedto increase in average household water savings from 5.36 to8.39 GPHD (Table 8). A positive trend on the increase of actualwater savings as increase in product satisfaction level shown onFig.1 in SupplementaryMaterial also corresponds to the correlationbetween the two parameters found in Table 5. Positive attitudes forwater conservation lead to strong intentions to engage in waterconservation behaviors (Russell and Fielding, 2010). Hence,thinking favorably (i.e., satisfaction) about the application processand the use of the product reflect positive attitudes on water con-servation. On the contrary, the two satisfaction factors (productsatisfaction and customer satisfaction during service installation)do not have a significant correlation with the changes in water use

Table 6Water saving potential index in relation to actual household water savings (GPHD).Actual household water savings are shown as meanwith lower and upper bounds at95% confidence level while excluding outliers (as shown in Fig. 1(a) insupplementary material).

Water saving potential index 1 2 3

Mean 9.00 8.23 10.80Lower bound 0.47 2.32 �9.49Upper bound 17.53 14.13 31.10

habits, whereas changes in water use habits were significantlycorrelated with the water saving potential (i.e., number of watersaving appliances installed), as shown in Table 5. Changes in wateruse habits may be highly variable and it is difficult to relate thechanges to participants’ satisfactory levels. However, the changes inwater use habits may have developed imperceptibly as the partic-ipants perceived the water conservation devices and that maycurtail the effectiveness of the water efficiency devices over time.

3.3. General effects of the program

The costumer survey included questions about the associatedeffects of the retrofit program (i.e., high efficiency fixtures) asshown in Fig. 2. Positive feedback (over 60.9%) were obtained forthe questions regarding the changes inwater use habits, savings onwater bill, recommending the program to others, and interest intrying new devices. The survey responses indicate that the partic-ipants had positive experiences with the water conservation pro-gram and were satisfied with the benefits of the high efficiencydevices.

Positive effects of the water conservation program were iden-tified in relation to observation of savings on water bill and changeinwater use habits. Significant correlations were observed between(1) observation of savings on water bill and interest in trying newdevices; and (2) observation of savings on water bill and recom-mending the program to others (Tables 4 and 5). These correlationsindicate that the effect of water use efficiency fixtures on water billresulted in positive attitudes for water conservation. Change inwater use habits only has significant correlation with the obser-vation of savings on water bill and positive attitude for recom-mending the program to others (Table 7). The correlation betweenthe changes inwater use habits and observation of savings onwaterbill indicate that there is a direct influence between the conserva-tion actions and anticipated savings.

Similar results were found in the high correlation betweenchanges in water use habits and recommending the program toothers, the participants may think the change in water use habits

0

20

40

60

Verydissatisfied

Dissatisfied Neutral Satisfied Verysatisfied

Uncertain

Pa

rtic

ip

an

ts

(%

)

Product satisfaction

Fig. 1. Customer’s satisfaction on different process of the program.

Table 7Satisfaction and associated effects of the program in relation to the change of wateruse habits.

Characteristics c2 pa

Satisfaction level Product satisfaction 4.24 0.644Customer satisfactionduring service installation

3.93 0.686

Associated effectsof the program

Change of water use habits 24.91 <0.001Interested in trying newwater savings devices

6.11 0.191

Recommended this programto others

6.27 0.043

a For chi-squared probability of greater than or equal to 0.05 indicates that thetwo parameters are statistically independent. For detail information please refer toTables 1 and 2 in supplementary materials.

65.6

32.8

1.6

76.6

9.414.1

60.9

39.1

0.0

70.3

28.1

1.60

20

40

60

80

100

YES NO Uncertain

Pa

rtic

ip

an

ts

(%

)

Savings on water billRecommended the program to othersInterested in trying new devicesChange of water use habits

Fig. 2. Responses from questions regarding the effects of the program: (a) Has thisprogram changed your water use habits? (b) Did this program help save you money onwater bill? (c) Have you recommended this program to others? (d) Would you beinterested in trying new water saving devices?

0

10

20

30

40

50

60

-300 -200 -100 0 100 200 300

Fre

qu

en

cy (%

)

aYear 1Year 2Year 3

30

40

50

60

ue

nc

y (%

)

b

M. Lee, B. Tansel / Journal of Environmental Management 128 (2013) 683e689 687

can be easily done, thus, they are more optimistic in recommendingthe program to others. The participants who have recommendedthe program to others had also perceived significant savings ontheir water bill (Table 4). Customers’ interest in trying new watersaving devices also had a significant correlation with changes intheir water use habits (Table 5). Positive responses to questions for“recommended this program to others” and “interested in tryingnew water saving devices” suggest strong support from the par-ticipants for further water conservation actions. Gilg and Barr(2006) reported that environmentalists are likely to believe thathelping the environment is socially acceptable and desirable. Thedesire for water conservation by installing water efficient devicesincreased when people perceive greater benefits from existing highefficiency fixtures (Lam, 2006). According to the theory of plannedbehavior (studying the relationship between attitudes and actions);people are more likely to engage in water conservation behaviors ifthey have positive attitudes toward water conservation (Russelland Fielding, 2010). These indicators can be used as to assess thewater conservation potential or willingness of customers to modifytheir water use behaviors.

Actual water savings from the participants were used to studythe correlation between the responses for changes in water usehabits and observation of savings on water bill, as shown as fre-quency curves in Figs. 3 and 4. No significant difference was foundbetween response (Yes and No) for the frequency curves of actualwater savings in relation to response in change of water use habits,while there was a significant differences in the frequency curves inrelation to response for observing savings in water bill. The fre-quency curves shifted towards higher actual water savings levelsfrom Year 1 to Year 2, and then shifted backwards to lower actualwater savings in Year 3. While the frequency curve peaks movefrom lower actual water savings towards higher actual water sav-ings representing increase in actual water savings over the period,on the contrary, when the peaks move backward (peaks at negativeactual water saving ranges) representing reduction in actual watersavings. This observation suggests offsetting behavior for the par-ticipants during the first two years of implementation. However,these offsetting effects decrease over time as people becomeaccustomed to the water efficiency units. This finding also

Table 8Product satisfaction level in relation to actual household water savings (GPHD).Actual household water savings are shown as meanwith lower and upper bounds at95% confidence level while excluding outliers (as shown in Fig. 1(b) insupplementary material).

Satisfaction level 3 4 5

Mean 5.36 4.45 8.39Lower bound �1.62 �1.29 2.68Upper bound 12.35 10.19 14.09

confirmed the rebound effect discussed by Campbell et al. (2004)that water demand declining by regulating installation of low-flow fixtures but inclining by giving free retrofit device kits.

Russell and Fielding (2010) indicated that there is insufficientinformation regarding the relationship between habits and actualwater use behaviors, as it is difficult to correlate the water usehabits. Actions of change inwater use habits are highly variable anddependent on the type of activities. Behavior change involvinghabitual factors will require intervention strategies that bear upconscious intentions in developing new behaviors into habits(Ouellette and Wood, 1998). For instance, Randolph and Troy

0

10

20

-300 -200 -100 0 100 200 300

Fre

q

Actual water savings (GPHD)

Fig. 3. Frequency analysis on the actual household water savings in relation toresponse in “Has this program changed your water use habits?” (a) Yes; (b) No.

0

20

40

60

80

100

-300 -200 -100 0 100 200 300

Fre

qu

en

cy (%

)

aYear 1Year 2Year 3

0

20

40

60

80

100

-300 -200 -100 0 100 200 300

Fre

qu

en

cy (%

)

Actual water savings (GPHD)

b

Fig. 4. Frequency analysis on the actual household water savings in relation toresponse in “Did this program help save you money on water bill?” (a) Yes; (b) No.

Table 9Synergistic interaction effects between the determinants on actual water savings.

Synergy index (S)a Productsatisfaction

Water savingpotential

Change of wateruse habits

Product satisfaction 2.40 3.04Water saving potential 2.40 �1.54Change of water use

habits3.04 �1.54

a S > 1 means synergism, S ¼ 1 means addictive and S < 1 means antagonism.

M. Lee, B. Tansel / Journal of Environmental Management 128 (2013) 683e689688

(2008) pointed out that reducing water use when showeringthrough reduction of showering time was more generally alteredfor residents. However, reducing frequency of showering may notbe a successful water conservation strategy since people may raiseconcerns about hygiene issues. Behavior is guided by habits orroutines (Steg and Vlek, 2009), that is, the majority of the waterconservation behaviors involved the “habit” factor. The behavioralchange in habits is closely related to actions that require a degree ofpersonal sacrifice (Gilg and Barr, 2006), for example, sufferingreduction in comfort by turning off water while soaping up. Per-sonal hygiene standards can also affecting the willingness ofchanging water use habits or accepting alternative water sources(Higgins et al., 2002; Pham et al., 2011). Moreover, people may haverelated their water consumption attitudes with their quality of life,thus, decreased their willingness of conserving water.

In addition, people may not have an accurate sense concerningtheir water use as they may under or overestimate their waterconsumption (Kolokytha et al., 2002). The gap between the statedattitudes and manifested actions (De Oliver, 1999) can be identifiedby comparing the responses to the survey for the question on“perceived water savings” and the “actual water savings”. The re-sults of observation of savings on the water bill were validated bythe actual frequency (in years) of observing water savings based ontheir actual water consumption data. Approximately 17.2% of theparticipants had the opinion of higher water savings than the actualquantities measured. Although the survey participants stated thatthey savedmoney on their water bill, the actual water use data onlyshowed one year of reduction. This number can be important in thedesign of water demand policy, as it implies a group of customers

are concerned about wasting water. On the contrary, only 1.6% ofthe participants underestimated their water savings. Similar resultswere found between frequency of observing water savings andchange in water use habits. This suggests that the majority of thecustomers (over 37.9%) in the program understand the impact oftheir water use habits and the associated water consumption.

3.4. Awareness of the program

A significant correlation was observed between water conser-vation programs advertised on TV and radio. However, most of theparticipants were not aware of other water conservation programspromoted by MDWASD or other organizations. Public informationregarding water conservation can be limited since customers maynot have access to all the resources. Kolokytha et al. (2002) claimedthat the public information levels were extremely low since ma-jority of the respondents asked for more information concerningwater issues, and the respondents were expecting to obtain theinformation from the water agency or local media (i.e., TV, radio).Moreover, the information should be focused on the skills/methodsof saving water based on the customer’s abilities (or behavioralknowledge) to directly influence water conservation behaviors(Corral-Verdugo et al., 2003).

3.5. Synergistic effects

The synergistic interaction effects of water-use-related de-terminants (i.e., water efficiency product satisfaction, water savingpotential, change in water habits) on actual water savings wereinvestigated by following the synergy index analysis proposed byChoi et al. (2011). The analysis was determined by equation as thefollowing: (Choi et al., 2011).

s ¼ ORABðORAb � 1Þ þ ðORaB � 1Þ (1)

Where ORAB is the odds ratio from combined effect, and, ORaB andORAb are the odds ratios from individual effect. The analysis can beused to examine if the interaction effect between determinants ismore than additive (i.e., synergetic, when S > 1) or antagonistic(S < 1).

As expected, incidence of perceiving of water saving was highestfor participants with product satisfaction and change of water usehabits, followed by product satisfaction and high water savingpotential. And, these determinants have shown combined effectson the actual water savings (S > 1). This finding confirms that thesatisfaction level has positive impacts on water savings and it doesadd synergetic effects to the water savings with combination ofwater saving potential and change of water use habits. On thecontrary, antagonistic interaction effect was defined for change ofwater use habits and water saving potential on actual water savings(Table 9). This suggests that the effects from change of water usehabits and water saving potential are independent. In addition, the

M. Lee, B. Tansel / Journal of Environmental Management 128 (2013) 683e689 689

impact of water saving potential on actual water saving is insig-nificant in this study (as discussed in Section 3.1).

4. Conclusions

The telephone survey of the customers who have participated inthewater conservation retrofit program provided data on thewateruse behavior of the participants, their satisfaction with the pro-gram, and associated effects from the program. The analysis ofsurvey responses indicate that water conservation behaviors arecorrelated with the level of satisfaction of the customers with theincentive program as well as high efficiency products. The surveyresponses provided insight for implementing effective water con-servation programs. Important findings include the following:

1. Attitudes: (1) customer satisfaction with the program andperformance/use of high efficiency devices lead to strong in-tentions to engage in water conserving behaviors; (2) cus-tomers who have referred the program to others were alsointerested in trying new devices, suggesting a strong interestfor further conservation practices.

2. Habits: changes in water use habits had direct influence on theparticipants’ perception of savings on their water bill.

3. Education level: education level of the participants had nosignificant effect on water savings.

4. Number of water saving appliances installed: the number ofhigh efficiency devices installed in the residences contributedto the changes in water use habits.

5. Synergistic effects: satisfaction level along with water savingpotential (i.e., implementation of water efficiency devices) orchange of water use habits has provided positive synergisticeffect on the actual water savings.

Significant offsetting behavior and rebound effects wereobserved among the participants. Frequency curves of the actualwater savings of the households showed that therewere significantincremental water savings during Year 1 and Year 2. There were noadditional savings during Year 3, which suggested that peoplebecome accustomed to the water efficiency units over time.

Acknowledgments

Partial funding of this research was provided by Miami-DadeCountyWater and Sewer Department (MDWASD). The authors alsoacknowledge the support from Miami-Dade County Sustainability,Planning and Economic Enhancement Department.

Appendix A. Supplementary data

Supplementary data related to this article can be found at http://dx.doi.org/10.1016/j.jenvman.2013.05.044.

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