Diarrhea is a health problem that can affect toddlers and is linked to environmental sanitation conditions. Poor household waste management and drinking water that does not meet microbiological standards can be environmental factors that potentially increase the risk of diarrhea. This study aims to determine the relationship between household waste management and drinking water quality and the incidence of diarrhea in toddlers. This study is a quantitative study with an analytical observational design using a cross-sectional approach. The sample consisted of 100 respondents selected using purposive sampling. Data were collected through questionnaires, observations, and laboratory testing of composite drinking water samples from nine villages. The results showed that 51 respondents (51%) had toddlers with diarrhea, while 49 respondents (49%) did not. The analysis revealed a significant association between household waste management and the incidence of diarrhea in toddlers (p-value = 0.005; PR = 1.833; 95% CI = 1.205–2.789).Laboratory tests showed that 44% of the samples tested positive for Escherichia coli and all samples tested positive for coliforms. The relationship between drinking water quality and the incidence of diarrhea could not be statistically analyzed because all respondents fell into the category of substandard drinking water quality. There was a significant association between household waste management and the incidence of diarrhea. Descriptively, drinking water quality was one of the factors contributing to the high incidence of diarrhea among toddlers.