There was recently a similar discussion here:
In that thread, the guy's pH actually was that high -- but the point is you don't care about the water's pH. What does the report tell you about alkalinity?
You should be making adjustments based on alkalinity, not water pH. That is probably in your report as well.
If your water supply has changed recently, and the pH really is different, it does not necessarily mean the alkalinity has changed significantly.
If you post your report, there are folks here who will tell you more than you ever wanted to know.