I live in a single family house but i can hear flushing noises in my master bathroom when there isn’t a toilet in the house being flushed and no water is running. It is like a toilet flushing next door.

That's a very plausible and likely explanation. Has it always been that way, or is this something that just started?

Start here:

1) Lift the toilet seat and see if you can see water trickling into the bowl. If you see water trickling into the toilet then the FLAPPER needs to be replaced to resolve the issue.

2) Lift the toilet tank lid and look into the tank...see if water is overflowing the tube in the center of the tank. If water is overflowing the tube in the tank then the FILL VALVE needs to be replaced.

3) Do these two things for ALL toilets in the home.

4) If you have a forced water heating system you could have AIR pockets in the system circulating around the house and causing gurgling noises. If this is the case then the heating system needs to have the air bled out of the system.

5) If you have a sump pump in the basement it could be that you have ground water coming into the sump pit and the sound you hear is the pump pumping the water out.

Check these things...post back as needed.

Mark

I first heard it periodically about a year ago. I hadn't heard it for a while but I have been hearing it occasionally the last few weeks again.

I think a check of your own system is a great idea just to eliminate it as a possible cause of that flushing noise. Keep a journal of this occurance and see if a pattern emerges like when windows are likely open because of the weather, or times of day/night, or other appliances like a washing machine in use. Let us know what you find.