This article critically reviews the presence and quality of studies on microplastics in drinking water and freshwater sources. Microplastics, defined as water-insoluble solid polymer particles ≤5 mm, have been detected in various water types, including drinking water, surface water, groundwater, and wastewater. The study assesses the quality of 50 studies using a quantitative approach, focusing on sampling methods, sample size, processing, storage, laboratory preparation, clean air conditions, negative and positive controls, sample treatment, and polymer identification. Only four out of 50 studies received positive scores for all quality criteria, indicating a need for improved quality assurance in microplastic sampling and analysis. Microplastics are frequently present in freshwaters and drinking water, with concentrations spanning ten orders of magnitude. The most common polymer types detected are PE, PP, PS, PVC, and PET, reflecting global plastic demand and density differences. Fragments, fibres, films, foams, and pellets are the most reported shapes. The authors conclude that more high-quality data are needed to better understand potential exposure and inform human health risk assessments.This article critically reviews the presence and quality of studies on microplastics in drinking water and freshwater sources. Microplastics, defined as water-insoluble solid polymer particles ≤5 mm, have been detected in various water types, including drinking water, surface water, groundwater, and wastewater. The study assesses the quality of 50 studies using a quantitative approach, focusing on sampling methods, sample size, processing, storage, laboratory preparation, clean air conditions, negative and positive controls, sample treatment, and polymer identification. Only four out of 50 studies received positive scores for all quality criteria, indicating a need for improved quality assurance in microplastic sampling and analysis. Microplastics are frequently present in freshwaters and drinking water, with concentrations spanning ten orders of magnitude. The most common polymer types detected are PE, PP, PS, PVC, and PET, reflecting global plastic demand and density differences. Fragments, fibres, films, foams, and pellets are the most reported shapes. The authors conclude that more high-quality data are needed to better understand potential exposure and inform human health risk assessments.