What might be the cause of a toilet on the first floor of our 2-storey house making an occasional gurgling or draining sound? The toilet tank isn't overfull or overflowing when the sound happens. The sound started a couple of months ago, a couple of times a day, but has increased to one every hour or so.
Thank you for any suggestions.

Toilet gurgling is usually a venting issue. You need to make sure the roof vent isn't plugged. I have found acorns, dead squirrels etc. in them.

Hi Ronar

I think I have a different take on this than Ma0641. Here, I'm thinking you might have a faulty FLAPPER. When you said the "sound started a couple months ago, a couple times a day but has increased to ONE EVERY HOUR or so", this does not sound like a bubbling or burping issue associated with flushing the toilet... instead, sounds like the toilet may be filling itself periodically after water has gotten past a defective flapper.

I would suggest you do a DYE TEST. Here, take some dark food coloring and drip maybe 15-20 drops into the toilet TANK only. Wait 15-20 minutes and then look into the toilet bowl. If you colored water in the toilet BOWL then the flapper is defective and needs to be replaced.

Your thoughts?

Mark

Good point. If it occurs periodically, without flushing, I agree with Mark. If the gurgling occurs upon flushing then venting may be the issue.