Abstract:
The Kapiti Coast, in the south-west of the lower North Island of New Zealand approximately 50 km north of Wellington, faces the threat of water shortage. Water shortage already acts as a constraint and will increasingly restrict economic and population growth. Additional abstraction from water resources is unsustainable for both the human and the natural systems. Garden irrigation and flushing toilets are the two household activities that consume the majority of potable water. However, these activities do not require water of drinking standard. Substituting grey-water for potable water for these two activities therefore offers considerable potential in alleviating the water shortage problem.
This study explores attitudes and perceptions to the re-use of domestic grey-water from washing machines, showers, and baths for garden irrigation and flushing toilets ("these household activities"). A postal survey of 107 households on the Kapiti Coast showed that: (a) Most respondents support the re-use of grey-water for irrigation (79%) and flushing toilets (59%); (b) Their major concerns relate to personal health, the health of plants and the environment, and financial commitment; (c) If a centralized grey-water re-use system was adopted, this could save 48 percent of the water used for these household activities during summer, and 27 percent in winter. If an on-site system was adopted, this would save 31 percent of the water used for these household activities during summer, 26 percent in winter; (d) Female respondents are more supportive of reducing potable water demand; (e) Different groups of people respond differently to the various policy instruments. Therefore, the local authority would need to adopt a range of policies, targeting different groups of people, to change their present water consumption behaviour, and reduce the demand for potable water.
