Assessing greywater management and reuse options for smallholder urban farmers and eatery operators in Mbarara City, Uganda

Abstract

Introduction: Rapid urbanisation, climate variability, and increasing water scarcity have intensified interest in greywater reuse for urban agriculture in developing countries. However, evidence on the management, quality and reuse potential of greywater from small-scale eateries remains limited. This study aimed to assess greywater management practices, microbial contamination, and stakeholder perceptions to evaluate its suitability for reuse in urban farming in Mbarara city, southwestern Uganda. Materials and methods: A mixed-methods approach was employed involving 80 participants (40 eatery operators and 40 smallholder farmers) across two administrative divisions. Data on greywater generation, handling and disposal were collected using questionnaires and interviews, while greywater samples from eateries were analysed for fecal indicator bacteria using standard methods, and findings were summarized using descriptive statistical analyses. Results: Eateries generated approximately 80 L of greywater per day, with disposal identified as a major operational challenge. Microbial contamination was widespread, with coliforms detected in 87.5% of samples and fecal indicators in nearly half. Poor disposal practices were associated with environmental challenges, including odours, mosquito breeding, and drainage blockage. Smallholder farmers reported persistent water shortage and expressed strong willingness to adopt treated greywater for irrigation and urban farming. Conclusions and implications: These findings highlight a critical gap between greywater availability and safe reuse in rapidly growing secondary cities. While untreated greywater poses clear public health risks; its consistent availability and stakeholder acceptance present significant opportunities for reuse following appropriate treatment. Strengthening decentralized treatment, hygiene practices, and policy guidance could enable safe integration of greywater into sustainable urban agriculture systems.