Rainwater and Greywater Use As Coping Strategies for Household Water Insecurity

Background and Purpose. Water is essential for human health and well-being. In many countries, water insecurity is of growing concern. In 2000, over 300 million people experienced seasonal water shortage. By 2050, this number may reach 1.3 billion. In some places, household rainwater and greywater harvesting have become important coping strategies. Rainwater is often collected in barrels under a roof gutter. Greywater is recycled from other domestic use, such as bathing or laundry. To date, surprisingly little is known about the extent, nature, and socioeconomic determinants of household rainwater and greywater use. Conducted in Baguio City, the Philippines—where rainy seasons bring abundant rain, while dry seasons bring city water stress—this study asks the following questions: To what extent and for what purposes do households use rainwater and greywater? What socioeconomic characteristics are associated with household rainwater and greywater use?

Methods. Data are from randomly-sampled household surveys (N=396) in an urban Baguio City neighborhood. Dependent variables are binary measures of household rainwater and greywater use, each measured separately for rainy and dry seasons. Independent variables are characteristics of (a) the household water manager: gender, education, marital status, age, and indigenous ethnic identity; and (b) the household: size, income, having savings, water storage capacity, access to the public utility, and homeownership. Descriptive statistics and multiple regression, with survey methodologies to account for stratified sampling design, were used.

Results. Rainwater and greywater are used by a majority of study households in seasonal ways. For rainy seasons, 81.2% of households report rainwater use, and 43.9% report greywater use. During dry seasons, usage rates reverse: 46.5% for rainwater and 88.4% for greywater. Rainwater is used in more ways than greywater in this setting. In the rainy season, rainwater is used for sanitation (77.3% of households), laundry (62.9%), cleaning (46.5%), bathing (21.7%), and cooking (9.1%). In the dry season, greywater is used mainly for sanitation (84.3%) and cleaning (22.5%). Multiple regression finds few associations between characteristics of the household water manager and dependent variables. Several associations are found, however, between household characteristics and dependent variables. Household size is positively associated with rainwater use in both seasons (p=.01, rainy; p<.001, dry) and greywater use in the dry season (p=.04). Income is negatively associated with rainwater use in both seasons (p=.03, rainy; p=.04, dry), but positively associated with recycled water use in the rainy season (p=.02). Finally, having household access to water from the public utility is negatively associated with rainwater use in both seasons (p=.01, rainy; p=.03, dry).

Conclusions and Implications. Findings suggest that rainwater and greywater use are widespread in the study setting, and may be valuable coping strategies for households with more members, often lower incomes, and less access to the public utility, in particular. Future research into the adoption and diffusion of these practices may inform policies that promote the dual goals of equitable water access and water conservation, in both the study setting and other contexts where water insecurity and environmental change are of increasing concern.