After returning from a two month vacation two of my three toilets were running. Also when I showered the pressure just about blew me away. Now I find out that one of my bathroom sinks is leaking. Could the city have increased the water pressure and not told us or do we have a pressure valve that has failed, and Where should I look for one.
Thanks

Usually they are not routinely installed. You may find one after the meter in the house, but it's highly unlikely. They are usually installed when there are problems in the home. The water pressure should be checked. The city could also have a regulator that failed somewhere. 40-50 PSI is good >80 PSI is bad. PSI is gauge pressure.

The pressure reducing valves are fairly common in areas with large differences of elevation. To give the people at the top of the hill decent pressure, you have to blow the guy in the valley away.