How to Fix a Cracked Toilet Tank, Bowl, or Base

How to Fix a Cracked Toilet Tank, Bowl, or Base

How to Fix a Cracked ToiletIf you notice your toilet is starting to show cracks, pay close attention to its nature and location. Some may be easy fixes, while others require that you buy a new toilet.

If you’re a handyman, follow the instructions below for fixable cracks. If you aren’t, give us a call and we’ll gladly get your toilet back to its pristine shape.

What Causes Hairline Cracks in Toilets?

You may be wondering how toilet bowls get hairline cracks in the first place. There are a few things that can cause these small cracks in your porcelain throne, including these common culprits:

Impact: Did something hit your toilet? A hairdryer? Or a heavy tissue box holder? Did someone slip and fall and hit the toilet on their way down? Any impact on your toilet can cause hairline cracks.

Age: As toilets age, they become more vulnerable to cracks. Although your toilet should last upwards of 50 years, we recommend checking the toilets in your home for signs of cracking.

DIY Projects: Sometimes DIY projects don’t go as planned. Something as simple as tightening toilet bolts a little too tight can lead to small hairline cracks in your toilet bowl.

How to Fix a Cracked Toilet Tank

First things first. Assess the size of the crack before thinking you can fix it yourself. If we’re talking about a hairline crack, get ready to be your family’s hero. But if your toilet tank has a significant crack, you’ll have to replace it.


  • Towels or washcloths
  • Plumber’s putty or silicone sealant


If the cracks are small or hairline cracks, do the following:

Step 1. Turn off the water supply to the toilet.

Step 2. Drain the tank of all water.

Step 3. Dry the tank until it’s bone dry (both on the inside and outside).

Step 4. Apply plumber’s putty or silicone sealant on the cracks.

Step 5. Wait the time recommended on the sealant manufacturer’s instructions.

Step 6. Turn on the water supply to the toilet.

Step 7. Fill up the tank.

Once you’ve followed all those steps, flush the toilet. If no water leaks, congratulations. You’ve just fixed your toilet.

How to Fix a Cracked Toilet Bowl or Base

If you walk into your bathroom and notice standing water on the floor, you may have a cracked toilet bowl or base. Make sure to monitor your family’s use of the shower, though. No sense in stressing over the toilet when the source is something else.

If it turns out that the issue is a crack in the toilet bowl or base, you’ll have to buy a new toilet. If doing so is not an option due to finances and if it’s a hairline crack and your toilet isn’t leaking, you can apply plumber’s putty or silicone sealant. Follow the steps in the section “How to Fix a Cracked Toilet Tank” to learn how to fix a hairline crack. However, this will only buy you a little bit of time, since the constant contact with water would eventually weaken the silicone sealant.

If the crack is significant and/or your toilet is leaking from the base, you’ll have to replace the toilet. To do this:


  • New toilet
  • New tank bolts (if the old ones are rusted)
  • Caulk
  • Wrench
  • Pliers (optional to help remove the tank bolts and/or water supply line)


Step 1. Turn off the water supply to the toilet.

Step 2. Empty the tank by flushing the toilet.

Step 3. Remove the tank bolts (located underneath the tank).

Step 4. Unscrew and remove the water supply line from underneath the tank.

Step 5. Remove the tank.

Step 6. Unscrew the base from the floor (you’ll need a wrench for this).

Step 7. Remove the base.

Step 8. Scrape any remaining wax from the hole on the floor.

Step 9. Align the new toilet with the bolt holes on the floor.

Step 10. Tighten the bolts with a wrench (use new bolts if the old ones are rusted). Don’t overdo it when tightening the bolts. Too much force to keep it tight may end up cracking your new toilet and you’ll be back to square one.

Step 11. Apply caulk around the base of the new toilet.

Step 12. Place the new tank over the new bowl.

Step 13. Tighten the bolts underneath the tank.

Step 14. Follow the instructions for your new toilet to install the parts inside the tank.

Step 15. Reconnect the water supply line.

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