A month ago I started to lose water pressure in my whole house when two water sources are on at same time. When one is on all is good. Called water company. They came out and said their pressure is good. Said maybe my regulator was bad and to just remove it because they only run 70psi. Did that and still have same issue. Don't seem to have a leak because meter doesn't run when not in use. So I am now at a loss. Any ideas? Home is only 7 years old and has PVC piping (modular).

Look for a valve on the main line that may not be completely open, including the valve at the street.

Did that. All valves r open. This problem just happened out of the blue. No work was being done on anything.

The water company checked your pressure where they come into the home. I'd also check at a fixture. The problem looks like pressure but it is most likely a volume issue likely caused by a restriction. Is it reduced on every fixture in the home?

Not sure where the WC checked the pressure at. I wasn't home. I'm assuming it was at the meter. Every fixture has great pressure when nothing else running. As soon as u turn on any other water source anywhere in the house, I lose pressure at both sources. Before I took off the regulator u had to turn off both fixtures to get the pressure back but now the pressure will return once the second fixture is turned off.