Physicochemical and Biological Quality of Groundwater in Kajiado County, Kenya

Contaminated groundwater is the most commonly reported source of waterborne diseases in Kenya being associated with 64% of the total water-borne diseases outbreaks across the globe. The need to evaluate the physicochemical and bacteriological quality of groundwater in the county is thus needed. Against this backdrop, the present study was set out to evaluate the physicochemical and bacteriological quality of groundwater in Kajiado county, Kenya. This study took both the descriptive and experimental research designs. From this population, a sa mple of 171 households was selected using stratified random sampling to ensure representative coverage across different settlement types. The target population was first stratified into three main categories based on settlement patterns: urban, peri-urban, and rural zones. Water samples were extracted from various sample boreholes and physical, chemical and bacteriological tests undertaken. The assessment of water treatment methods in Kajiado County, Kenya, revealed that 40% of households consistently treat their water, 35% do so occasionally, and 15% never treat their water, with boiling (30%) and chlorination (25%) as the most common methods (40% cited cost and 30% ease of use as main influences). Correlation and regression analyses identified total coliform counts as the strongest negative predictor of groundwater safety (r = -0.736, p < 0.01; Beta -0.90 to -0.94, p ≤ 0.005), with turbidity also negatively correlated (r = -0.404, p = 0.03), while physicochemical parameters showed weaker or insignificant associations, highlighting microbial contamination as the primary threat to water safety in the region. The study concludes that groundwater quality in Kajiado County is influenced by a combination of chemical, biological, and physical factors, but bacteriological safety remains a paramount concern. The study recommends prioritizing the mitigation of bacteriological contamination in Kajiado County through improved sanitation infrastructure and public health interventions. The study also recommends promoting water treatment technologies, enhancing monitoring of natural sources, improving septic system management, investing in tap water infrastructure, and educating communities on safe water handling practices.