We had a similar problem shortly after moving into our home in 2006. Gurgling in the shower when the toilet was flushed. We got a plumber to come out and clear the line. He said it happens either from drywall finishers dispose of extra joint compound down the toilet or tilers dispose of extra grout or adhesive. He also noted that painters had apparently stood on our toilets when doing the walls around them as they were scratched badly. All fixed under warranty.
I agree that it would be prudent to watch for any signs of impaired drains and call warranty or a plumber ASAP.
|