The current research included the evaluation of some elements, including Mg, Fe, Pb and Cd; in drinking water before and after their passing through water filters. High levels of most heavy elements are toxic to cells of the living organisms. The present target elements had been collected from five areas; three governorates: Cairo, Giza and Qalyubia beside Mostorod and Faculty of Education, where concentrations of their drinking water had been evaluated before and after passing through water filters. Finally, the results have been compared with recommendations of WHO. The results showed that Qualubia drinking water contains the highest concentrations of Mg, Pb and Cd while the Mostorod`s water showed the highest concentration of Fe before filtration. After using the filter for water of the three governorates; Cairo, Giza and Qualubia, the concentrations of the four target elements decreased to equal or less than the safe concentrations recommended by WHO, except Cd that exceeded the safe level of Giza`s water. Concerning Mg, resulted low concentrations of it in water of the five target areas and much lower than safe levels recommended by WHO and thus do not require water filter