Where in the country is the water most basic or alkali?

In the United States, the most basic or alkaline water is typically found in the western regions, particularly in areas like the Great Basin, which includes parts of Nevada and Utah. The high evaporation rates and mineral deposits in these areas contribute to elevated pH levels in lakes and groundwater. Alkaline lakes, such as Mono Lake in California, are prime examples of this phenomenon, often exhibiting pH levels above 9.