Tried to figure this one out in the archives but have failed so far.
At 4:45 every AM for about 15 min the pipes are tapping about once every second. It stops only when water is running or the main shut off into the house is turned off.
I have turned off the water to the drip system, washing machine, and the hot water heater so far with no effect. I have adjusted the pressure regulator in and out and that also had no effect.

I am going to turn off the toilets tonight but I am not holding my breath that the toilets are that timely.

This problem only happens at 4:45 in the AM and not any other time of day and has been happening for at least 3 weeks.

I called the city today and they had no idea but said they would put a pressure gauge on one of the hydrants around the house if it continues.

Thanks for taking a look