Viabilidade da utilização de água de reuso em jardins domésticos – Estudo de caso

Abstract

Water is essential for the survival of all living beings. The preservation of the ecosystem requires responsible use and reuse of this resource. In order to conserve water resources, several alternative water sources have been employed to meet human activity needs. Among the various implemented solutions, rainwater harvesting is a widely accepted measure due to its ease of implementation and its benefit of reducing treated water consumption in households. This study analyzed the technical and economic feasibility of using reused water, specifically rainwater, for the irrigation of residential gardens. Classified as a technical-project case study, the research adopts as its basis a fictional single-family residence located in Goiânia – GO, with a catchment area and garden area of 200 m². The technical approach employed was based on the premise of system efficiency for a household inhabited by four adults, with the collected rainwater being used exclusively for garden irrigation. The methodology is organized into four stages: collection of climatic and consumption data; design of the capture, pumping, and irrigation system; cost analysis; and evaluation of the investment payback period. The study considered the parameters of NBR 15527 (ABNT, 2019) and used spreadsheets for calculating the rainwater harvesting system, as well as online quotations and SINAPI tables (July 2025 reference) for cost analysis of materials and equipment. This economic analysis revealed the implementation costs (totaling R$ 14,403.22), the savings the system can generate (30 m³ of water), and an approximate 74% reduction in the monthly water bill. It is concluded that a return on investment can be achieved in a period of just over three years.