For reference, this is about a newly purchased (and built) house in
Fort Worth, TX...

I woke up the other day to an annoying (though somewhat quiet) sound
of drumming originating from my master bathroom.

The master bathroom has two sinks and emitting from one of the sinks
was drumming sound. After a while it would go away and then later it
would come back again... very odd.

I checked underneath the sink and didn't notice anything odd. The
pipe itself didn't seem to be making any noise.

When I stopped up the drain, the noise stopped. Very odd!

I finally tracked it down to the heater of all things. Whenever the
heater would turn on, I'd start to hear the drumming noise again. I
popped out the drain stopper and took a look down the drain.

What I could see was water displacement since it was rippling a bit
down the drain.

Apparently, whenever the heater turns on, it's pushing air up through
the sink somehow! When I put my hand over the drain, I could feel air
pressure from the drain matching the pulsing of the drumming sound.

Anyhow, does anyone here have any suggestions on how I might go to
alleviate this problem? Is this a heater problem or a plumbing
problem? It only just started about a month after I moved in (and I
had used the heater a few times without hearing this sound). Maybe
this is normal and my water just isn't draining right?

No other sinks in the house make the sound except for this one.

How are the heater and sink connected so that air would come out of
the sink?

I was thinking that it might have been a sympathetic vibration, but I
think it's air being pushed through the water in the drain.

Any suggestions are appreciated!

- Samiel