When any of my water taps (kitchen, bathroom) are opened there is high pressure. This lessens immediately. I also have started having drips from shower heads which stop if another nearby water source(toilet, sink) is open.

After initial burst of high pressure water pressure is normal.
Any ideas?

when any of my water taps (kitchen, bathroom) are opened there is high pressure. This lessens immediately. I also have started having drips from shower heads which stop if another nearby water source(toilet, sink) is open.

after initial burst of high pressure water pressure is normal.
any ideas?
Yeah! I think I can take the mystery out of it for you. Your burst of high pressure is caused by expansion. Let me explain. As the water heats in the water heater it expands out into the system. If there'[s a check valve or a backflow preventer installed the water has no place not expand to so it builds up pressure that you relieve every time you open a faucet. It makes no difference if the faucet you open is hot or cold. The solution is to install a expansion tank,(see image) on the water heater cold water supply. Just cut in a tee upstream from the cold water shut off and mount a expansion tank and your problem goes bye-bye. Good luck, Tom