1.11.1 Water Efficiency Households Retrofit Through Rainwater Harvesting, an Ancestral and Ongoing Drinking-Water Source

The objectives of this research were: i) to propose a domestic water efficiency retrofit (WER) prototype implementing a rainwater harvesting system (RWHS), ii) determine the RWHS efficiency, and iii) evaluate the social perception about the WER acceptance and implementation in a single-family household (SFH). The WER prototype was developed in a SFH. The SFH is located in the basic geostatistical area (BGA) 2736 in Acapulco, Gro. Mexico. The RWHS catchment surface area was 29 m2, 50% of the total roof slab area. The device comprises a first-rain separator (20 L) and a storage tank (1,200 L). The rainwater harvesting potential (RWHP) was evaluated during two consecutive rainy seasons (2020 and 2021). The harvested rainwater quality was analyzed in samples from 2021. The water analyses carried out were alkalinity, pH, electrical conductivity, total dissolved solids, chlorides, nitrates, and sulfates. Additionally, 168 surveys were applied within the BGA 2736 to the SFH owners to evaluate their perception about the acceptance and possible reconversion of the SFH. The RWHP was ca. 44 and 20.51 L/m2 in 2020 and 2021, respectively. All the quality rainwater parameters evaluated met with the NOM-127-SSA1-1994. Moreover, the perception study showed that 95% of those surveyed are willing to modify their households into a WER. The observed results were encouraging. Due to the RWHP and the harvested rainwater quality, the WER of a SFH poses as a promising eco-technological solution to address the hydric stress global issue based on the circular economy concept.