Understanding daily water use in Karachi: Smart water metering in constrained environments

Karachi, Pakistan Smart water metering research overlooks urban South Asia, where intermittent supply, reliance on multiple water sources, power outages, and poor connectivity make such systems challenging. Thus, existing studies, predominantly focused on the Global North, do not provide hydrological insights relevant to populations facing these conditions. This study designs and implements a smart flowmeter system to measure household water use in Karachi, Pakistan. The smart flowmeter can withstand power and network outages of 60 hours and 13 days respectively, while the flowmeters are installed creatively to enable accurate measurement of both intermittent piped water supply and non-piped sources of water. We fit machine learning and hierarchical mixed-effects models on the resulting data to quantify the impact of factors that affect daily household water use. We find that per capita water use is significantly lower than water utility’s assumptions. For the first time, we identify a statistically significant increase of over 7 % in water consumption on Fridays, a Muslim religious holiday. Water use was found to increase with maximum daytime temperatures exceeding 31°C while piped water shortages in the summer months constrained overall water use. Current understanding of household water use in Muslim-majority countries is based on monthly aggregated data; this study provides the first daily-scale hydrologic insights into household water use dynamics in such a setting. • First smart water metering study to analyze daily household water use in South Asia. • Per capita water use is significantly lower than water utility’s assumptions. • Statistically significant increase in water use on Fridays, a Muslim religious holiday. • Water use rises with temperature but only beyond a 31°C threshold. • Volume of intermittent piped supply serves to constraint water use.