Community preferences for recycled water in Sydney

Abstract

A sample of over 800 Sydney households was surveyed using the internet about their preferences for increased waste water recycling in the context of urban expansion in Western Sydney. The choice modelling approach was used to estimate household willingness to pay for increased volumes of recycled water supply, and for alternative end uses of the recycled water, including industrial, open space irrigation, domestic and environmental flows. The results demonstrate positive community preferences for increasing recycled water supply, and an aversion to household use amongst households not already using recycled water. Respondents’ first preference was for recycled water to replace potable water in industrial uses.

Keywords:

• Wastewater
• recycling
• choice modelling
• Sydney

Notes

1 A copy of the questionnaire used for this study is available on request from the authors.

2 Respondents who answered the questionnaire in less than four minutes were excluded from the sample. Other respondents were excluded because they only partially answered the questionnaire.

3 The questionnaire provided information about Sydney's current water supply and supply sources, wastewater disposal and recycled water use. The survey then outlined how Sydney's water needs would increase in the future with population growth, that much of this population growth would occur in Western Sydney and how Sydney's extra future water needs could be supplied and extra wastewater disposed. After reading this information, respondents answered questions that self-assessed their prior awareness of these issues.

4 This model was selected as the preferred model following an examination of a large number of candidate models, which allowed for non-linear marginal utility over volumes, interactions between volume and other explanatory variables, and a range of respondent characteristics as covariates.

5 Latent class models offer an alternative approach to modelling heterogeneity by using discrete rather than continuous distributions.

6 Households already connected to recycled water would not benefit in terms of additional private use from future recycling. We suspect their higher WTP may be due to perceptions of fewer health risks as a consequence of their experience with the good.

Additional information

Funding

Funding from the Australian Water Recycling Centre of Excellence for the research presented in this paper is gratefully acknowledged.