Journal of Advances in Microbiology

Unsafe personal hygiene and handwashing contribute significantly to repeated exposure to waterborne diseases in informal settlements. This study examined the influence of personal hygiene practices on the incidence of waterborne diseases in Mathare informal settlement in Ngong, Kajiado County, Kenya. A descriptive cross-sectional study using mixed methods was conducted between February and May 2026. Structured questionnaires (n = 334), an observation checklist, focus group discussions (N = 17), and a retrospective analysis of clinical data from three neighbouring health facilities (Ngong Sub-County, Zamzam, and Kenswed) were used for data collection. Statistical analysis included descriptive statistics, chi-square tests ( ), Pearson correlation (r), and binary logistic regression. The results showed a significant difference between reported behaviour and observed hygiene conditions. While 75% of respondents reported washing their hands after using the toilet (mean = 3.90, standard deviation = 1.18), direct on-site observation showed that only 25.1% had a designated handwashing station near the facility and only 12% had soap. Notably, 80% of households faced shortages of soap and water due to serious financial constraints (mean = 2.10, standard deviation = 1.09). Binary logistic regression showed that handwashing with soap was significantly associated with lower disease occurrence (Mean = -0.985, p < 0.001, OR = 0.373), corresponding to a 62.7% reduction in the odds of disease. The study concluded that high health literacy was undermined by substantial economic barriers that may sustain faecal-oral transmission. Subsidised soap programmes and low-cost handwashing infrastructure are recommended.