Prevent Water Damage

• Before you do anything, top the water from overflowing out of the toilet. Turn the knob on the water valve, which sticks out of the wall behind or next to the toilet, clockwise until it is hand-tight. This will shut off the water supply to the toilet. If the toilet does not have a water valve, or if the toilet continues to run, close the main water valve for the house. Mop up any water on the floor before it causes damage or mold growth begins. If there is a room below the toilet, look at the ceiling there to see if water is staining the ceiling or coming through.
  
  

Visible Obstruction

• By looking into the top of the toilet's drain opening, you may see that a foreign object has caused the toilet clog. If you do see the obstruction, you can put on rubber cleaning gloves and reach into the drain to pull the obstruction out. While this may not be a good option for someone with a weak stomach, your plumber will likely do the same thing and charge you for it. You can use a straightened wire hanger to reach into the drain opening, keeping a hook on the end, but you run the risk of scratching the toilet's bowl.
  
  

Plunger

• A plunger comes in handy when you have a toilet clog, especially if you have the right kind of plunger. Funnel-cup plungers have a curved piece on the underside of the cup, allowing the plunger's cup to fit into the bottom of the toilet better. This better fit allows a funnel-cup plunger to exert more pressure on the toilet's drain, which can dislodge clogs that sit closer to the top of the drain. You need to give the plunger a chance, though, and pump the handle up and down at least 12 times before giving up on it.
  
  

Auger

• A toilet auger, also called a snake, has a long, flexible line with a corkscrew on one end, as well as a handle. You must feed the auger's flexible hose down the toilet's drain line as you spin the line clockwise. Once you have dispensed the entire flexible line, you spin the line counterclockwise as you pull it back out of the drain. Sometimes the auger will not clear a drain after one use, so give the auger up to three tries before you contact a plumber. Feed the auger down a different portion of the drain opening each time, increasing the chances you eliminate the clog.