Aluminum is an abundant metal, but it does not dissolve easily into water so it is not often a concern in drinking water.The main source of aluminum in the body is food.
Although natural water can contain from 0.1 to as much as 9.0 parts per million aluminum, by far the main source of aluminum in drinking water is alum (aluminum sulfate) that is added by water treatment plants to aid in clarification. (Alum causes tiny particles to clump together, making them more easily filterable.)
Alum is listed by EPA in Secondary Standards at a suggested level of 0.05 to 0.2 ppm.
Treatment: How to Remove Aluminum from Water
Aluminum can be removed by a cation exchanger (water softener) but this is not regarded as a practical home treatment because regeneration of the exchange bed must be done with sulfuric or hydrochloric acid.
Home treatment of drinking water is easy. Reverse osmosis and distillation remove 98 percent plus. Aluminum can, under the right pH conditions, be a foulant to reverse osmosis membranes.
Claims are made by manufacturers of KDF/Carbon filters that KDF removes aluminum, but we can find no evidence to support this.
Aluminum is also removed by electrodialysis.