Contamination of freshwater with microplastics (MPs) has become one of the primary issues for human health as being a major source of drinking water. Recent studies have reported varying results for MPs regarding the MP concentrations in raw water, the efficiency of water treatment and the distribution systems, as well as the analytical technique employed. The aim of this study is to investigate the MPs in the drinking water supply system through samples collected from the raw, treated and tap water of Amsterdam (the Netherlands) over a period of 6 months in 2022. Plastic particles ≥700nm were identified and quantified using a selective and sensitive analysis using pyrolysis gas chromatography coupled to mass spectrometry (Pyr- GC-MS). As the target polymers (PE, PP ,PS ,PET ,PVC and PMMA) were found at least in one of the raw and treated water samples, PE and PVC were frequently detected in tap water. Given the ubiquity of MPs in freshwater, this study contributes to the knowledge of MP pollution in drinking water supply system and provide important data for the estimation of human exposure to MPs.