The study focused on assessing the impact of human resource information systems (HRIS) on employee performance at Nairobi City Water and Sewerage Company (NCWSC) Ltd., with particular emphasis on e-recruitment, e-training, and e-payroll management. Using Social System Theory and the Technology Acceptance Model as a foundation, the study treated employee performance as the dependent variable and HRIS elements as independent variables. A descriptive research design surveyed all 89 employees using a Likert scale questionnaire, and data analysis was conducted with SPSS software, applying descriptive and inferential statistics, including multiple linear regression. Results indicated that e-recruitment and e-performance appraisal significantly enhanced employee performance, while e-training had a more limited effect unless aligned with specific job needs. Overall, NCWSC employees held positive views on HRIS, especially regarding e-recruitment and e-performance appraisal, which were shown to support organizational goals effectively. The study recommended aligning e-training with role-specific skills to improve outcomes. It also suggested that future research could examine HRIS impacts in different sectors and the influence of organizational culture and top management support on HRIS effectiveness. The study implies that aligning HRIS functionalities, particularly e-recruitment and e-performance appraisal, with specific organizational and job-related needs can significantly enhance employee performance and support strategic goals in the water and sewerage sector.