Solar PhotoVoltaic (PV) systems are becoming increasingly common, so it is critical to understand how system or component failure impacts lifetime costs. Reliability analysis uses historical performance data to help identify equipment or systems that perform badly. A case study of solar PV systems' dependability and Life Cycle Cost (LCC) analysis is presented in this research. Manufacturers and consumers of solar PV systems provide the information needed for reliability study. This research incorporates reliability analysis into the assessment of rooftop solar PV systems' LCCs in a composite climate. Failure and maintenance costs are a major contributor to total LCC, as demonstrated by estimating failure rates using Weibull++ modeling. ReliaSoft's Weibull++ software is used to estimate the best-fit failure distribution. Initial expenses, failure, Operation and Maintenance (O&M), and net salvage value are the categories into which the lifetime costs are divided. According to the analysis, inverters and balance-of-system elements are important sources of cost. The Mean Time Between Failure (MTBF) of earthing and grounding, DC CB, IGBT, AC CB, Grid, AC converter, relay, inverter, cooling fan, and SMBUS communication components is lower; however, since they need only modest repairs, this expense is covered by routine inspection. Understanding how costs affect a product's whole life cycle is made easier with the use of the LCC study. The cost of O&M accounts for around 74% of the overall LCC. Thus, it may be inferred that the LCC of the solar PV system was driven by O&M and failure costs. It gives the user an idea that O&M expenses associated with panel cleaning can be substituted by manual cleaning for small solar PV systems like those examined in this paper. Since failure costs are lower than O&M costs, it is possible to lower this cost by scheduling an ideal technician visit for routine inspection. The results indicate that PV system sustainability can be improved by implementing cost-effective technologies and optimizing maintenance procedures. Long-term performance monitoring, battery storage integration, and circular economy methods for recycling PV components should be the main topics of future research.