Toilet Leaking From the Bottom? How to Fix It
Short answerWater at the base of a toilet usually means the wax ring or seal under it has failed, often because the toilet rocks on loose bolts. First rule out a leak from above, such as the supply line or tank. Then shut off the water, lift the toilet, clean the flange and install a new seal.
Safety first
- Stop using the toilet until it is fixed. Water at the base can contain waste, so wear gloves and clean the area with detergent.
- Turn the shutoff valve behind the toilet clockwise and drain the tank before you lift anything. A toilet is heavy, so get a helper.
- Dry the floor within 24 to 48 hours to help prevent mold.
Likely causes
| Cause | How to tell | What fixes it |
|---|---|---|
| Failed wax ring or seal | Water appears at the base after you flush, sometimes with a sewer smell. | Lift the toilet and install a new seal. |
| Loose floor bolts | The toilet rocks when you sit on it. | Tighten the nuts a little at a time, alternating sides. If it already leaks, reseal it, because rocking can break the seal. |
| Water coming from above | The tank bolts, the supply line or the shutoff valve is wet, and water runs down to the floor. | Tighten or replace the leaking connection or gasket. You may not need a new seal at the base. |
| Cracked bowl or damaged flange | You can see a crack in the porcelain, or the flange is broken when you lift the toilet. | Replace the toilet or have a plumber repair the flange. |
What you need
- New wax ring or wax-free seal
- New closet bolts
- Putty knife
- Adjustable wrench
- Rubber gloves
- Bucket, sponge and towels
- Hacksaw, if bolts need trimming
How to fix it
- Find where the water starts. Dry everything with a towel. Check the supply line, the shutoff valve and the bolts under the tank. If those stay dry and water shows up at the base after a flush, the seal is the likely cause.
- Shut off the water and empty the toilet. Turn the shutoff valve clockwise, flush and hold the handle down, sponge out the rest of the water in the tank and bowl, and disconnect the supply line.
- Lift the toilet. Remove the caps and nuts from the floor bolts. Rock the toilet gently to break the seal, lift it straight up with a helper, and lay it on towels.
- Clean and check the flange. Scrape off all old wax from the flange and the bottom of the toilet with a putty knife. No wax should remain. Look for cracks, rot in the floor, or a flange sitting well below the finished floor. Replace the bolts.
- Install the new seal. Follow the directions on the seal package for your flange height. Set the toilet straight down over the bolts.
- Tighten and test. Put on the washers and nuts. Press down on the bowl and tighten, alternating sides. Do not overtighten, because the bowl or flange can crack. Reconnect the water, flush several times and check for leaks. If the toilet rocks and sits 3/16 inch or less off the floor, shim it.
When to call a professional
- The flange is broken or set well below the floor.
- The floor around the toilet feels soft or spongy, which can mean rotted wood.
- It still leaks after a new seal.
What it costs to have fixed
Toilet Replacement is estimated at $230 to $910 nationally. See your state
Common questions
Why is my toilet leaking from the bottom when I flush?
Flushing sends water past the seal under the toilet. If the seal has failed, some of that water escapes at the base. A leak that shows up only after flushing points to the seal rather than the tank.
Can I just caulk around the base?
No. Caulk does not repair a failed seal. The water and waste keep leaking underneath, where they can damage the floor without being seen.
Can I tighten the bolts to stop the leak?
Tightening can stop rocking, but it will not repair a seal that has already failed. Tighten gently and alternate sides, because too much force can crack the porcelain.
Can a toilet leak without making any noise?
Yes, EPA WaterSense says a worn flapper can leak silently and waste thousands of gallons a year. To check, put a few drops of food coloring in the tank, and if color shows up in the bowl after 10 minutes, it is leaking. Flush right away so the tank does not stain. Source
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Last verified 2026-11-01
Sources
- Fluidmaster: 7530 Toilet Seal Kit Instructions — Removing the toilet, cleaning the flange and toilet bottom, replacing bolts, tightening alternately with downward pressure, not overtightening, and flange height checks
- Fluidmaster: Wax Free Toilet Seal — Shimming a toilet that rocks by 3/16 inch or less
- NC State Extension: Preventative Home Maintenance — Checking around the toilet and below it for leaks and wood damage
- CDC: About Mold — Drying wet areas within 24 to 48 hours
- Kohler: Toilet Troubleshooting — Leaks at the flush valve gasket on two-piece toilets and not overtightening
General information, not professional advice. Conditions, codes and prices vary. Turn off power, gas or water before any work, and hire a licensed professional when in doubt. Cost figures are our estimates, not quotes.