Microplastics have been detected in drinking water and its sources, prompting concerns about human health risks. This review critically assesses the quality of 50 studies on microplastics in drinking water and freshwater sources, including river, lake, groundwater, tap, and bottled water. The studies also reviewed wastewater data. The review evaluates sampling, extraction, and identification methods, and provides a quantitative assessment of study quality. Microplastics are frequently found in freshwaters and drinking water, with concentrations spanning ten orders of magnitude (1×10⁻² to 10⁸ #/m³). However, only four studies received full scores for all quality criteria, indicating a need for improved sampling and analysis methods. The most common polymers are PE ≈ PP > PS > PVC > PET, likely reflecting global plastic demand and sedimentation tendencies. Common shapes include fragments, fibers, films, foams, and pellets. The review highlights the need for high-quality data to better understand exposure and inform human health risk assessments. The study emphasizes the importance of standardized methods, proper sample handling, and reliable polymer identification to ensure data quality. Overall, the review underscores the variability in study quality and the need for improved methodologies to accurately assess microplastic risks in drinking water.Microplastics have been detected in drinking water and its sources, prompting concerns about human health risks. This review critically assesses the quality of 50 studies on microplastics in drinking water and freshwater sources, including river, lake, groundwater, tap, and bottled water. The studies also reviewed wastewater data. The review evaluates sampling, extraction, and identification methods, and provides a quantitative assessment of study quality. Microplastics are frequently found in freshwaters and drinking water, with concentrations spanning ten orders of magnitude (1×10⁻² to 10⁸ #/m³). However, only four studies received full scores for all quality criteria, indicating a need for improved sampling and analysis methods. The most common polymers are PE ≈ PP > PS > PVC > PET, likely reflecting global plastic demand and sedimentation tendencies. Common shapes include fragments, fibers, films, foams, and pellets. The review highlights the need for high-quality data to better understand exposure and inform human health risk assessments. The study emphasizes the importance of standardized methods, proper sample handling, and reliable polymer identification to ensure data quality. Overall, the review underscores the variability in study quality and the need for improved methodologies to accurately assess microplastic risks in drinking water.