Earth Day, celebrated annually on April 22, reminds us of the importance of preserving our planet for future generations. A vital element to sustaining life is water, which covers 71 percent of the Earth. Across the United States, water sources vary widely, ranging from freshwater lakes and rivers to underground aquifers and reservoirs, each playing a crucial role in water supply. Depending on the geological composition of a region’s water source, the amount of dissolved minerals in the water can differ.