Leaky toilet bowl

Leaky toilet bowl: Water under the bowl

A leaky toilet bowl is usually a more serious problem than a leaky toilet tank. But repairing a leaky toilet bowl can be handled by a capable do-it-yourselfer. The two most common reasons for a leaky toilet bowl are a faulty wax gasket or a cracked bowl.

Repairing a leaky toilet bowl

Before doing anything else, turn off the water at the shut off valve behind the toilet and flush the tank until the tank and bowl have emptied. This will keep additional water from leaking onto your floor while you handle the repair.

Next, inspect your toilet bowl to determine if the water is leaking from beneath the bowl, a faulty gasket, or from a crack in the bowl itself. Once you have determined the source of your leak, proceed to the appropriate instructions below for repairing your leaky toilet bowl.

Replace a Wax RING
Wax ring to fix leaky toilet bowl.
A new wax ring to fix a leaky toilet bowl.

If water is leaking from beneath the bowl the wax gasket has failed and should be replaced. This is also called a was ring or a wax seal. The gasket is simply a wax seal that fits between the sewer pipe and the toilet to keep liquids from escaping. Replacing a faulty gasket is a fairly involved procedure and many homeowners opt to have a plumber handle the repair. If you wish to proceed on your own you can follow these instructions:

  1. Turn off the water at the shut off valve and flush the toilet until the tank and bowl have emptied. Use a sponge or old towel to wipe out any remaining water.
  2. Disconnect the water supply lines from the toilet tank.
  3. Remove the nuts holding the toilet to the floor. These may be difficult to remove, but pliers and some oil, such as WD-40, will help.
  4. Gently rock the toilet back and forth to break the seal with the gasket. Be careful not to damage the connection between the tank and the bowl.
  5. Thoroughly clean all of the old wax and debris from the underside of the toilet and the floor flange.
  6. Unwrap and place the new wax seal on the floor flange with the curved side of the wax seal facing up, toward the bottom of the bowl. The bolts should remain in place, or be replaced as needed.
  7. Carefully place the toilet back on top of the wax seal, being certain to keep the toilet level. Apply pressure on the toilet to seat it properly against the wax seal. You can carefully sit on the toilet to apply some weight.
  8. Replace the nuts and tighten by hand. Be careful not to over tighten and crack the toilet.
  9. Reconnect the water lines to the toilet tank and slowly turn the water on to fill the tank.
  10. Flush the toilet to fill the bowl and check for leaks.
  11. If all is well, you can apply a silicon caulk around the base of the toilet.
Cracked Toilet Bowl

If the bowl is cracked it should be replaced. You will most likely be replacing the toilet and tank together as a set, to make sure the style and colors match exactly. If you are only replacing the bowl, disconnect the bolts connecting the two and set the tank aside.

Replacing a toilet is a fairly involved procedure and many homeowners opt to have a plumber handle the repair. If you wish to proceed on your own you can follow these instructions:

  1. Measure the space available for the new toilet, to make sure your replacement will fit.
  2. Turn off the water at the shut off valve and flush the toilet until the tank and bowl have emptied. Use a sponge or old towel to wipe out any remaining water.
  3. Disconnect the water supply lines from the toilet tank.
  4. If you are saving your old tank, now would be the time to remove the bolts attaching the tank to the bowl. If not, leave the two connected and you can discard them as one unit.
  5. Remove the nuts holding the toilet to the floor. These may be difficult to remove, but pliers and some oil, such as WD-40, will help.
  6. Gently rock the toilet back and forth to break the seal with the gasket.
  7. Thoroughly clean all of the old wax and debris from around the floor flange.
  8. Unwrap and place a new wax seal on the floor flange with the curved side of the wax seal facing up, toward the bottom of the bowl. The bolts should remain in place, or be replaced as needed.
  9. Carefully place the new toilet on top of the wax seal, being certain to keep the toilet level. Apply pressure on the toilet to seat it properly against the wax seal. You can carefully sit on the toilet to apply some weight.
  10. Replace the nuts and tighten by hand. Be careful not to over tighten and crack the toilet.
  11. If you saved your old tank, you can reinstall in now. You may want to replace the rubber seal between the tank and the bowl if it looks damaged.
  12. Reconnect the water lines to the toilet tank and slowly turn the water on to fill the tank.
  13. Flush the toilet to fill the bowl and check for leaks.
  14. If all is well, you can apply a silicon caulk around the base of the toilet.

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