Turbidity poses a big problem in water treatment. One of the processing stages in the water treatment unit is the coagulation/flocculation process to remove turbidity. This study uses coral stone and oyster shell powder as locally available natural coagulants to reduce water turbidity. Coral stone and shell powder have now been widely used as a natural coagulant in reducing Mn, Fe levels. However, using coral stone and shell powder as a natural coagulant is still debated. To determine the effectiveness of using coral stone and shellfish powder as natural coagulants in reducing Mn, Fe, and water turbidity levels using the backwashing method. This research is an experimental study with a pretest and post-test design. The population in this study was all water in community dug wells that were cloudy and contained high levels of Mn, Fe, and a sample of 100 liters was taken for filtering experiments and samples for checking levels of Mn, iron (Fe), and water turbidity. This research was conducted at the Health Polytechnic of the Aceh Ministry of Health from July to November 2021. The water analysis was carried out at the Health Laboratory of the Aceh Environmental Health Department. The laboratory tests were analyzed using the paired t-test and the ANOVA test. The results showed an effect of the treatment of coral stone and clamshells on the decrease in Fe content with a P-value of 0.012 (α < 0.05). Likewise, the Mn content affects the treatment of coral stone and shell powder with a thickness of 40 cm, 30 cm, and 20 cm, which affects the decrease in Mn content with a P-value of 0.001 (α < 0.05). The results showed that Fe levels before entering the shelter had a significant difference with the processing of coral and shell powder with a thickness of 40 cm, 30 cm, and 20 cm. Coral and shells with a thickness of 40 cm, 30 cm, and 20 cm with 15 repetitions can reduce Fe content from 5.2476 ppm to the lowest at 2.4747 ppm. Coral Rock and Shell Powder Effective as a ........