Plunge the Bowl

• If the water level in the bowl drops over time, plunge the toilet to clear out any partial clogs from the trap. A toilet paper clog that drapes over the bend in the trap will slowly siphon water out of the trap and down the drain pipe, lowering the water level in the bowl. Plunging can eliminate a partial clog in the trap.
  
  

Adjust the Float

• The float in the toilet's tank affects how much water stays in the tank. In general, you want the water level to be about an inch below the top of the overflow tube for the toilet to flush with enough pressure. Adjust a float that's on the end of a metal rod by bending the rod upward. The float will sit at a higher level, causing the tank to fill with more water. For floats that travel up and down on a metal rod, use the plastic screw on the top of the float or the metal clip on its side to adjust it higher up the rod.
  
  

Test With Dye

• Dropping dye in the toilet's tank will show you if it's leaking, which will lower the tank's water level. If you don't have dye, use dark food coloring. Place a few drops in the tank and watch where the dye goes. If the tank has a leak, the dye will gravitate to the location of the leak and eventually leak out of the tank. If the water is leaking from crack in the tank, you must replace the whole tank.
  
  

Tighten or Replace Nuts

• If the leak isn't from a crack in the tank, try tightening nuts or other parts at the site of the leak. Be careful not to overtighten nuts or other parts or you might crack the tank. Some parts will need to be replaced if tightening doesn't stop the leak. If the leak involves the flapper, which opens to let water out of the tank, remove it and install a new flapper that will seal correctly.