African Violets and Water

I have been having trouble getting my African Violets to bloom.  I had one that in the recent past was a prolific bloomer but lately hasn't has any blooms.  I have usually watered my violets with tap water.  But I noticed that when the city changed from getting our water from the river to well water that my plants stopped blooming.  So, I decided to do something different when watering. I switched to distilled water. My Grandma always kept African Violets and only used distilled water to water and had beautiful blooming violets. So for the past few weeks, I switched to watering with distilled water.  Now, I have blooms. The violet pictured still has a way to go to full health but it has blooms.  I still have one violet that still hasn't bloomed at all.