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Fix Toilet Leaks

Toilets are one of the most common sources of leaks in the home, usually unnoticed by the residents because the leaks are often silent and out of view. Even the new high-efficiency toilets can be water wasters. A leaky flapper valve or an improperly set water level in the tank can cause significant water leakage. And not every “running” toilet makes noise. Even though you think your toilet is not leaking, there is one sure fire way to find out.

Lift the lid off the toilet tank and put 10-15 drops of dark-colored food dye or toilet dye tablets into the tank. After 15 minutes, check the color in the toilet bowl. If there is any sign of the dye color, your toilet is leaking. If the water level looks fine but the dye test shows that the toilet leaks, the two most common culprits are the valve seat, which may need to be cleaned; and the flapper (or tank ball), which may need to be adjusted, cleaned, or replaced.

Instructions for replacing fill valves and flappers are included on this page.

The picture below will help you to identify the components of a toilet:


TOILET LEAKStoilet_components_2

Toilets are the most common source of water waste in the home, usually through the overflow pipe or the flapper. A leaking toilet can waste 50 to 90 gallons of water per day.

Two important parts inside the tank are the flush valves "overflow pipe” and the flapper. The overflow pipe is the safety net for your toilet. When properly set it will prevent water from overflowing. The flapper releases water when the toilet is flushed and stops water from running continuously after the tank fills with water.

Flush valves are designed to be tall so that they can work with all model toilets; large and small. The top of the overflow pipe should be below the tank lever hole by as much as 1 inch to ensure the water does not overflow onto the floor. The water level should be indicated by a mark on the tank, the overflow pipe (depending of the age or use of the toilet), or a water stain on the inside of the tank. The water level should be set about 1 inch below the top of the overflow pipe.

Leaking flappers are the second most common problem on a toilet. When water seems to trickle through a toilet long after it has been flushed, a worn rubber flapper is probably to blame. When the toilet is flushed, the flapper lifts, letting water flow into the bowl. As the tank empties, the flapper sinks to block the opening, which allows the tank to refill. With age, the flapper can wear, become brittle and debris or minerals can get in the way of a good seal.  When replacing flappers, it is imperative that you use the flapper recommended by the manufacturer. These flappers are designed so that the toilet flushes 1.6 gallons per flush (gpf). Using the wrong flapper could convert your 1.6 gpf toilet to 3.5 gpf.


  1. Close the water supply to your toilet or turn off the water to the house.
  2. First and foremost, read and always follow manufacturer installation instructions. Also, once the brand and type is identified, you can go to the manufacturer’s website for How to Repair Instructions. Additional DIY videos can sometimes be found on
  3. Flush the water in the tank and soak up any remaining water. Disconnect the water supply line to the tank.
  4. Remove the fill valve nut and then the old fill valve.
  5. Place the valve shank onto the fill valve, then insert the fill valve into the tank opening.
  6. Connect the supply line.
  7. Attach the refill tube (trim if too long) and clip the tube to the overflow pipe.
  8. Turn the water back on.
  9. Allow the tank to fill.
  10. Adjust the water level by turning the head of the screw in the counter clockwise direction to raise the float (water level) or turn clockwise to lower water level. To lower water level you must first flush the tank.