I had a customer with the same problem and when I checked the WP was 197# .
I thought my pressure gauge was bad and got another one and it showed 195# so I knew the reading was right.
This was causing the old old style ball cock fill vale to turn on by its self.
What was more amazing was that she refused to allow me to install a PRV and Exp. Tank. after repeated warnings.
I made her sign on the invoice that I was not responsible for any damage to the home if there was any kind of failure or flood after I left.
That is the highest pressure I have ever encountered coming off the street.
If they are on a septic system the constantly running toilet may have filled the tank, especially if it was near the point of needing to be pumped.