We note that the pH of the effluent is between 6.2 and 7.1; this variation between one country and another is possibly due to the variation of ambient temperature and variability of the effluent as a function of time. For filtered water, the pH varies between 7.32 and 8.55; this can be explained by the variability in wastewater (input filters) on the one hand and the difference in characteristics between the two filters, on the other hand. The maximum 8.55 was recorded at the level of the crushed glass filter. We also note that filtered water pH values are still significantly higher than the values of wastewater (input); this could be due to the dissolution of some existing salts during the flow of the effluent causing some chemical reactions inside the filters.