I recently renovated our bathroom, including new plumbing and a new sewer line that runs almost to the foundation. The toilet and tub have separate vents going up through the roof (these are the originals, cast iron). Today, when I was taking a shower, I started hearing bubbling sounds from the toilet and the water level in the toilet was very low. I would be quite surprised if there were a blockage in the sewer line (though, of course, that is a possibility), so I'm wondering what else could be the problem.

Thanks!
-- buddhababy

Hey Budd,
Sounds more like the tub was venting through the toilet. Are you sure they weren't "gurgles" that you heard? When a vent's blocked and the fixture vents through the toilet the suction will lower the water level in the bowl. The solution would be to snake the bathroom vents. Put out enough cable to reach the base and 20 feet more. Good luck, Tom