Aluminum-containing chemicals, called alum or aluminum sulfate, are used to treat most surface waters. These chemicals trap dirt and then form large particles in the water that settle out so very little aluminum stays in the water.
Considerable publicity was given to some studies suggesting that more people were diagnosed with Alzheimer's disease in areas where drinking water contained small amounts of aluminum. According to most Alzheimer's disease experts, these reports are not accurate.
Aluminum is a natural chemical that occurs in many foods, including tea. Even if you live where the level of aluminum in drinking water is much above average, your intake from food would be about 20 times your intake from drinking water.
Aluminum is not regulated by the EPA because there is no reliable scientific data that shows it's dangerous.