Cirata Hydroelectric Power Plant (HPP) is one of the largest hydroelectric facilities in Indonesia, consisting of eight turbine units with a total installed capacity of 1,008 MW. As a critical component of the Java-Bali power grid, its operational reliability and availability are essential to ensure a continuous electricity supply. This study aims to analyze the impact of forced outages on the reliability and availability of each unit at Cirata HPP. A quantitative approach was employed using a Markov model to evaluate reliability and availability based on historical outage data from 2015 to 2022. The data analyzed includes the frequency and duration of forced outages for each unit. Results indicate significant performance variations across the units, with Units 2, 7, and 8 demonstrating the highest reliability levels (above 0.99). In contrast, Unit 3 recorded the lowest reliability and availability, at 0.8509 and 0.8955, respectively. This underperformance was attributed to a high number of outages and relatively long repair times. Component-level analysis revealed that the generator in Unit 3 was the primary contributor to reduced reliability, achieving only 0.4339 at 1,000 hours of operation. Based on reliability curve simulations, preventive maintenance for the Unit 3 generator is recommended every 830 hours of operation to maintain reliability above the minimum threshold of 0.5. This study concludes that implementing a preventive maintenance strategy based on reliability analysis can enhance unit performance and reduce the risk of unscheduled forced outages. The findings provide valuable insights for maintenance planning and reliability improvement at Cirata HPP and other hydroelectric plants.