If you do have a clog, and water is over flowing, the best thing to do is turn off the water to that fixture. For example if your toilet is overflowing just after flushing, shutting the water off at the valve should stop the overflowing. If the water does not stop overflowing at the fixture, make sure no other fixtures are running. All drains in your home connect together at some point, and a blockage can cause other drains to overflow as a result.
Have towels at the ready to absorb water on the floor, and use a bucket to remove as much water as you can from the bowl, or sink.
Call us immediately.