Calcium carbonate (CaCO3) was used as a filler in the mixture for plastic pipes to improve the mechanical properties of the product, this research dealt with the study of the effect of increasing the proportion of calcium carbonate (CaCO3) on the properties of the produced pipe through a factory application by preparation of five mixture of polyvinyl chloride with different proportions of calcium carbonate (3, 5, 8, 10, and 15)% with some additional materials for the manufacture of the plastic pipes by using the extrusion method to produce polyvinyl chloride pipes (110mm × 10bar × 6m) for transportation of drinking water,a series of tests were carried out on the raw materials: (bulk density, free flow and sieve analysis) and also on the final product: (dimensions, heat reversion, tensile strength, impact strength, resistance to external blows and strength characteristics determined by long-term hydrostatic strength (rupture), the results of the tests showed a decrease in the tensile strength by increasing the percentage of calcium carbonate addition and by a small amount up to 8% and the decrease became more clear when the percentage of calcium carbonate addition was more than 8%, the results obtained at the level of factory application have proved the possibility of increasing the proportion of calcium carbonate in the mixture of raw materials used in the manufacture of unplasticized polyvinyl chloride (U.P.V.C) pipes (from 3 to 8 %) and the results of the tests on the final product conformed to the certified specification for the proportion of 3, 5, and 8% and did not conform to the certified specification for proportions 10 and 15%.