I own an older home, 75 to 100 years, and among some of its quirks the latest one has caused me some concern. This began yesterday and it did it again tonight. Yesterday while I was taking a shower the other bathroom’s toilet began to bubble. Nothing came up, but it drained the bowl and continued to make a gurgling noise. It then happened in the bathroom where I was taking a shower. Tonight, after my wife finished her bath and pulled the plug the bathroom toilets did the same thing.
What’s causing this? I certainly don’t want to walk in one day and have things going in reverse.
The first thing that comes to mind is your vent system. Water flowing down a drain has to be displaced by air, ( think of turning a soda bottle upside down) hence the vent system in a house or building. Could be a number of things plugging the vent and causing air to be drawn in through the fixtures. If it started suddenly, as you say, I’d look for animal or bird activity that has restricted the air flow in the vent.
Could also be a collapsed line in a very old house, or if you’ve had any other drainage problems recently, it could be that solids have been forced into the vent system.
I second A.R.Cane. If the draining liquid cannot be followed by air,it creates a vacuum and pulls air from wherever it can.The toilets are providing it in this case.
Take a look on your roof, the vent pipes (there may be several) should have some kind of cap or heavy mesh screen to keep critters from building nests and/or getting inside.
Here are a couple of sites that may help:
http://www.askthebuilder.com/newsgator/000099.shtml
Thanks for the response. I’m glad it’s a vent and nothing serious.