Evaluating the Potential Reduction of Domestic Outdoor Water Demand Through Rainwater Harvesting in Vancouver

Increasing water demands attributed to population growth and climate change highlight the need to adopt practices, such as rainwater harvesting, to reduce water demands. In Vancouver, the irrigation of lawns and gardens from May to September is a major constituent of domestic water demands. The extent to which rainwater harvesting can help reduce domestic water demand in Vancouver has been neglected in research. This study aims to evaluate the capacity of rainwater harvesting to reduce domestic outdoor water demands under two water use settings.

To achieve the objective of the study, the monthly irrigation demand and the monthly amount of rainwater that can be harvested during the irrigation season for a typical home in Vancouver was calculated. A comparison was made between the monthly irrigation demand and the monthly rainwater harvesting potential to determine the proportion of domestic outdoor water demand that can be offset through rainwater harvesting.

Several variables had to be estimated, assumed and standardized when calculating irrigation demands and the rainwater harvesting potential. The results of the study can help residents and policymakers in Vancouver realize the benefits that rainwater harvesting can provide and, in particular, the extent to which outdoor water demand can be reduced.