You know the signs of a backed up toilet: the bowl is overflowing, and the rest of the family runs for cover.
Your natural inclination is probably to get as far away as possible from the germs and gunk within and to reach for your phone. You'll probably get a busy signal - there's a reason plumbers are the busiest repair people around.
Be brave: You can fix a backed up toilet yourself, often in a few simple steps.
Consider the case where you flush the toilet, and the water in your toilet bowl continues to rise above its normal level after you flush.
This is not a pretty picture, but if you've got kids who have recently discovered the wonders of toilet paper, it may well be a familiar one.
The first move to keep a bad situation from getting worse is to remove the top of the tank and flip the rubber stopper in the bottom of the tank back over the drain hole.
This will stop the flow of water into the bowl. Next, place the plunger and put the plunger cup snugly over the bowl's drain opening and give it a few vigorous pumps.
The idea is to force the obstruction beyond a U-shaped section of toilet pipe, called the "trap," and into the straighter (and broader) drainpipe. The blockage should then flow away and take with it any back-up water.
If it does not, try a slightly different tact: Plumbing with petroleum jelly. Apply a thin ring of petroleum jelly around the rim of the rubber plunger cup. Doing this provides for a tighter seal against the bowl - and improves the effectiveness of the pumping action.
Now try again, placing the plunger cup snugly over the bowl's drain opening and give it a few vigorous pumps.
If your second effort doesn't clear the backed up toilet, the problem may lie elsewhere in the sewer drain.
Now that you've ruled out a simple clog, it's time to call that busy plumber. While you wait: