Our well water has high pH as well as a high "total alkalinity" number. The latter is the bigger problem because it has longer lasting effects. A high alkalinity number means that the water resists acidification. Essentially it is like watering with a mild liquid limestone. That's been okay for us in East Texas because our soil is extremely acidic, so watering with high alkalinity water is fairly preferable, as far as I've been able to see. I'm guessing it helps to counteract the acidity in the soil. But if our soil wasn't acidic to start with, I know we'd have a big problem on our hands. Our water has over 600 ppm total alkalinity.
