We investigated the abundance of microplastics in freshwater, treated water, and household tap water from the drinking water supply chain in Changsha, China. The abundance was 2173–3998 (mean = 2753), 338–400 (mean = 351.9), and 267–404 (mean = 343.5) particles L −1 in freshwater, treated water, and tap water, respectively. Fibrous and fragments made up the majority (> 70%) in all water samples, and most polymers were composed of polyethylene, polypropylene, and polyethylene terephthalate. Microplastics in tap water were related to materials of transportation pipelines in drinking-water supply chain. Although plastics are corrosion-resistant, the slight fragmentation and abrasion may occur during drinking water treatment transportation. This study provided a proof for the occurrence of microplastics in drinking water, which may offer a reference for microplastic removal during drinking water treatment, and the formulation of standards for microplastic content in drinking water.