Best management practices (BMPs) are a continuous cycle of implementation, monitoring and refinement. Lack of perception on BMPs that are implemented based on the literature impedes the system`s capacity to fulfil its purpose to regulate stormwater volume and peak flows and attenuate pollutants. In this study, a series of monitoring in hybrid multi-functional BMP system was conducted to determine the performance as well as the irregularities during actual storm events. This system was connoted as hybrid wherein it is defined as a technology that integrates and incorporates several functions such as, infiltration, filtration and retention in a single system to overcome spatial constraints. It has two adjacent treatment tanks serving the infiltration and retention functions. The infiltration function of the hybrid BMP aims to treat stormwater runoff for groundwater recharge while the retention function allocates treated water to a subsurface extended detention basin. Moreover, it has an overflow tank adjacent to the retention tank to allow bypass of excess stormwater runoff. Based from the results, TSS is the most removed pollutant parameter for both infiltration and retention followed by the organics and appreciable load reductions were observed in nutrient and heavy metal parameters. Loads discharges at the infiltration and retention function were 68-92% lower compared to inflow loads. It has also been found out that regardless of sudden increase and decrease in loading rates during a storm event, the discharge of most pollutants in the infiltration, retention and overflow continuously decrease with respect to time. However, problems were uncovered during monitoring. It has been identified on the water balance as the rainfall depth increases the water entering the infiltration and retention tank decreases while larger the amount of water was being bypassed to the overflow. Based from the results, it can be recommended to renovate the facility to reduce the water being bypassed out of the system in order to allow more stormwater runoff to pass through the infiltration and retention unit. The results obtained can provide guidelines for this newly developed system and will render valuable information to allow the system top perform at its optimum.