​Bacterial contamination in fruits and vegetables cultivated in urban and peri-urban areas constitutes a serious public health risk. This paper investigates bacterial contamination in irrigation water of the Nairobi-Machakos counties interface, Kenya. Sixty-six irrigation water samples were tested for total coliforms, Escherichia coli, Shigella spp. Pseudomonas aeruginosa, Enterococcus faecalis, Vibrio cholerae, Salmonella typhi, BOD, COD, and pH. Results show a high load of bacterial pathogens in all samples except for Salmonella typhi, which tested negative. Based on Kenya's standards and WHO guidelines, the irrigation water samples are unfit for fruit and vegetable irrigation. Urgent and effective measures are required, including regular monitoring, sensitisation, and enforcement of phytosanitary and regulatory measures.​