Water is essential for all life forms. The water we intake every day can be contaminated by natural sources or industrial effluents. One such contaminant is fluoride, which in excess harms health like children’s black brains, dental fluorosis, arthritis, osteoporosis, chronicle issues, etc. The World Health Organization (WHO) advises a fluoride level in drinking water of 0.5–1 part per million (ppm). Modern techniques employed in defluoridation are very expensive and time-consuming, which will result in the need for cheap and efficient methods that we could easily implement in our houses. This study emphasizes the effectiveness of a biosorbent—tea ash in the elimination of fluoride ions, determining adsorbent dosage, pH, and optimum contact time for defluoridation. This approach has the benefit of making a cheaper and more environmentally friendly solution to the risk produced by the consumption of water containing fluoride.