High fluoride groundwater appears with alkali volcanic activity along Great Lift Valley in east Africa. Tanzanian people in Great Lift Valley are also suffering drinking water including high fluoride ( > 1.5 mgF/L of WHO). We investigated the groundwater and river water fluoride pollutions in Arusha area of Mt. Meru watershed and Moshi area of Mt. Kilimanjaro watershed in May, September, 2018 and March, 2019 to provide the solutions to this issues as No. 6 of SDGs. We find some results below: 1) Water fluoride boundary is appeared between Mt. Meru (4.0 mgF/L in average) and Mt. Kilimanjaro (0.5 mgF/L in average) watersheds. 2) Waters with high fluoride show Na-HCO3 type water, and fluoride increase with Na. 3) Groundwater fluoride tends to be increasing with residence time and depth of well, but in recent twenty five years, fluoride is higher in younger groundwater. 4) Well waters supplied to Arusha city come from the source recharge zone of 2,000 m to 3,000 m in altitude of Mt. Meru, and the fluoride content tend to increase with the recharge altitude.