Consequences of drinking harvested rainwater with lower pH

We are promoting rainwater harvesting in Guatemala. Water analysis indicated that the harvested rainwater has a lower pH value than what the U.S. Environmental Protection Agency suggests. They say water pH value is a secondary drinking water standard and recommend a pH between 6.5 and 8.5 for drinking water.  The pH of the harvested rainwater in our area varies between 4 and 5.  Are there any negative effects on the human metabolism drinking water with low pH level? Can we slightly increase the pH level by any household water treatment methods?