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Fix a toilet that leaks at the base

We'll confirm the leak is at the base, check the bolts, replace the wax ring if needed, and tell you when to call a plumber for flange damage.

Troubleshooting · Home plumbing
30–60 min
What you'll need
  • New wax ring (standard or extra-thick for low flanges)
  • Wrench or socket for closet bolts
  • Towels or rags
  • Putty knife or scraper (for old wax)
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Steps

Goal: Confirm the leak is at the base, then fix it by tightening bolts or replacing the wax ring.

  • Wipe the floor dry and watch where water appears when you run water or flush. Base leaks pool around the toilet; tank leaks drip from above.
  • Good: Water pools at the base. Proceed to Check bolts first.
  • Bad: Water drips from the tank or supply line. See a tank or supply-line guide.

Check bolts first

Goal: Rule out loose closet bolts before removing the toilet.

  • Remove the caps covering the closet bolts at the base. Check if the toilet rocks.
  • Gently tighten the bolts alternately—a quarter turn each—until snug. Do not overtighten; that can crack the porcelain.
  • Dry the floor and run water into the bowl. Wait a few minutes.
  • Good: No more pooling—bolts were the cause. See Verification.
  • Bad: Water still pools—proceed to Replace wax ring.

Replace wax ring

Goal: Remove the toilet, inspect the flange, and install a new wax ring.

  • Shut off the water at the valve. Flush and sponge out the bowl and tank. Disconnect the supply line.
  • Unscrew the closet bolts and lift the toilet straight up. Set it on towels. Plug the drain with a rag.
  • Inspect the flange for cracks, breaks, or rust. Confirm it is level and secure. If the flange is damaged, call a plumber.
  • Scrape old wax from the flange and toilet horn. Press a new wax ring onto the flange (horn down) or onto the horn.
  • Align the bolts in the flange slots. Lower the toilet straight down—do not rock it. Press down firmly.
  • Hand-tighten the nuts alternately. Reconnect the supply and turn the water on. Check for leaks.
  • Good: No water pooling. Toilet is stable.
  • Bad: Leak continues or flange is damaged—call a plumber.

When to get help

Call a plumber if:

  • The flange is cracked or broken.
  • The floor is soft or damaged.
  • You see sewage backing up.
  • The leak continues after replacing the wax ring.
  • You are not comfortable lifting the toilet.

Verification

  • No water pooling around the base after flushing and waiting several minutes.
  • Toilet is stable with no rocking.
  • No leaks at the supply connection.

Escalation ladder

Work from the device outward. Stop when the problem is fixed.

  1. Confirm leak location Verify water pools at the base, not from tank or supply line.
  2. Tighten bolts Check and tighten closet bolts; do not overtighten.
  3. Replace wax ring Remove toilet, inspect flange, install new wax ring, reinstall.
  4. Call a pro Flange damaged, floor soft, or leak persists—call a plumber.

What to capture if you need help

Before calling support or posting for help, have these ready. It speeds everything up.

  • Whether the leak is at the base, tank, or supply line
  • Bolt tightness and toilet stability
  • Flange condition (cracks, height, attachment)
  • Steps already tried

Is water pooling at the toilet base?

Wipe the floor dry and watch where water appears. Base leaks come from under the toilet; tank leaks drip from above.

Wipe the floor dry. Run water into the bowl or flush. Watch where water appears. Good: water pools around the base—base leak. Bad: water drips from tank or supply line—different guide (tank or supply).

Yes No

You can change your answer later.

Are the closet bolts loose?

Loose bolts can cause rocking and leaks. Tighten alternately; do not overtighten.

Remove bolt caps. Check if the toilet rocks. Gently tighten the closet bolts alternately—a quarter turn each. Do not overtighten. Good: bolts were loose, now snug—dry floor and test. Bad: bolts already snug—wax ring likely failed.

Yes No

You can change your answer later.

Does the leak stop after tightening?

Dry the floor and run water. Wait a few minutes.

Dry the floor. Run water into the bowl. Wait a few minutes. Good: no more pooling—leak fixed. Bad: water still pools—replace the wax ring.

Yes No

You can change your answer later.

Is the flange intact and level?

The flange must be intact and properly set. A cracked or low flange needs a plumber.

Shut off water. Drain and remove the toilet. Inspect the flange for cracks, breaks, or rust. Confirm it is level and secure. Good: flange intact—replace wax ring and reinstall. Bad: flange cracked or broken—call a plumber.

Yes No

You can change your answer later.

Replace wax ring and reinstall

Scrape old wax. Install new wax ring. Lower toilet straight down. Tighten bolts alternately. Reconnect supply. Test for leaks.

Done

Leak fixed

The leak stopped after tightening the bolts. Monitor for a few days to confirm.

Done

Call a plumber

Call a plumber if: the leak is not at the base (tank or supply); the flange is cracked or broken; the floor is soft; sewage is backing up; or the leak continues after replacing the wax ring.

Done

Reviewed by Blackbox Atlas

Frequently asked questions

Why does a toilet leak at the base?
Common causes: a failed wax ring (worn or misaligned), loose closet bolts, or a cracked or improperly set flange. The wax ring seals the toilet to the drain; when it fails, water and sewage can seep out.
Can I fix a toilet base leak myself?
Yes. Tightening loose bolts and replacing the wax ring are DIY tasks. If the flange is cracked, too low, or the floor is damaged, call a plumber.
When should I call a plumber for a base leak?
Call a plumber if the flange is cracked or broken, the floor is soft or damaged, you see sewage backing up, or the leak continues after replacing the wax ring.

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