The use of suitable glaze compositions, which enable ceramic sanitaryware (such as sink, toilet bowl, toilet bowl, etc.) to have better hygienic, aesthetic and technical properties, is of great importance as in other ceramic products. Glaze compositions, which provide durability to sanitaryware materials, reduce impact resistance and give ceramic material a hygienic appearance, are produced as ~97% white color depending on the preferences of the consumers, therefore, surface defects attract more attention in glazing and post-glazing process applications. When faults occurred during the different stages of manufacture detected on the final product, failure to detect faults on the final product by passing many production stages poses a problem in terms of intervention in the process. Faults that occur during glaze preparation are important in terms of cost. Since it is a stage in which many economic evaluations have been made in production, eliminating the faults caused from glaze preparation prevents further financial loss. In this study, the appearance of the faults in the sanitaryware items and the change in their regions (occured as a result of the oils contaminations from the machinery and components used in the preparation of glaze, the pipes of the tanks used in the glaze transport tanks and the glaze transfer or the impurities contaminated from the environment, the splashing of the impurities by the colored glazes in the glazing cabinets etc.) were characterized by means of SEM (Scanning Electron Microscopy), XRF (X-ray fluorescence spectrometry), XRD (X-Ray Diffractometry) and color measurement (L a* b*) analyses. According to the data derived from the final defected products, the faulty products were imitated by using the same components and methods on the plates under the laboratory conditions. Finally, the solutions for the problems were determined on the basis of faulty products obtained in the laboratory.