All toilets in the house suddenly gurgled
The 4 toilets on all 3 floors of my house and the washing machine's drain line started gurgling for one minute with no reason. The action died off. No one was using water or flushing at the time. We then had 4 people flushing each toilet simultaneously. Repeated twice. The flushes were normal. All sinks seem to be draining fine as well. Any reason behind this? Should I be concerned?