Water is essential for humans. So, it is used from agriculture to industrial products. However, due to the increase in population, contamination of water systems has often occurred. The quality of contaminated water and wastewater used for flushing and toilet waste has been compromised. Therefore, in order to prevent pollution problems of receiving waters, water treatment is proposed. As mentioned by Omran (2011), there are six steps in the water treatment process: pretreatment, aeration, coagulation and flocculation, sedimentation, filtration, and addition of chemicals to the clean water tank (exemplified in Figure 1). Before undergoing the treatment water treatment process, the raw water is allowed to flow into the preliminary treatment which begins with the first screening process. In this process, large floating materials such as leaves, sticks and fish are removed to avoid damage to the plant's equipment (Omran, 2011). Secondly, water goes through the process of aeration where the process of bringing water and air into close contact by introducing air bubbles and letting them rise into the water (Omran, 2011). According to Omran (2011), this process is used to remove gas trapped in water, such as hydrogen sulfide, which can produce unpleasant water instead of working well at pH below 6.5. A study conducted by Olumuyiwa, Fred, and George (2012) found that carbon dioxide in water is reduced rather than decreasing water solubilization through the aeration process. This causes corrosion and leaching of plumbing materials into the water. Subsequently, after undergoing the process of screening, aeration and other pre-treatment, the next process, the third, is known as coagulation and flocculation......half of the paper.... ..residual and does not cause problems of taste or odor (Water Supply System, 2013). The final stage of the water treatment system is adjusting the pH before supplying the water to the customer. Many treatment processes such as disinfection and coagulation are pH dependent. Basically, pH is an indicator of the acidic or alkaline state of water. The pH scale ranges from 0 to 14; 7 indicates the neutral point. The normal pH range of drinking water is between 6 and 8.5. Sodium carbonate (sodium carbonate) and sodium hydroxide (NaOH) are added to the water system to raise or lower the pH of the water to near neutral, while reducing the taste of soda and increasing effectiveness of chlorination. This method also decreases the potential for pipe corrosion as water with a pH above 9 can corrode metals such as brass, copper, zinc, aluminum and iron (Adam, Wang, Loftin & Meyer, 2002).