<p> Heavy metals, especially arsenic, have become a hot research topic due to their high toxicity and low removal efficiency in drinking water. Biofouling is one of the main factors affecting the removal efficiency of point-of-use (POU) water filtration systems. However, limited information is available on the effect of biofouling on heavy metal removal by POU systems. The aim of this study was to investigate how biofouling affects the removal efficiency of heavy metals,  especially arsenic, by different POU systems. Daily water use patterns in the U. S. households were simulated under laboratory conditions for the operation of POU systems. Sodium acetate was added to tap water to simulate an assimilable organic carbon source that contributes to biofouling formation and the concentration of sodium acetate gradually increased from 100 μg/L to 400 μg/L.  Sodium meta-arsenate (100 μg/L) was added to tap water to test its removal efficiency by POU  systems. Biofouling development and metal removal efficiency were monitored and correlated.  The results showed that arsenic removal efficiency and biofouling were positively correlated in both the activated carbon (AC) and reverse osmosis (RO) POU systems. Other conditions, such as temperature and flow rate, were negatively correlated with metal removal efficiencies in both systems. Overall, biofouling has been shown to contribute to improved removal efficiency of arsenic by POU, and the promotion effect was more significant in AC systems than in RO systems.  The results may contribute to an improved understanding of the maintenance of POU systems for heavy  metal removal </p>