Korky 6000BP wax-free seal
$12.49 at Amazon
Check it on AmazonPrice as of Oct 23, 2026, 5:30 AM EDT
Toilet leaking at the base: find the cause
Tell a bad floor seal from a tank leak, a supply drip or sweat, then fix it.
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Quick answer
Dry the floor and watch. After a flush, at the front or sides: the floor seal (wax ring). Down the back from the tank: tank bolts or gasket. By the wall, flush or not: the supply line. A cold, beaded tank: sweat.
Floor seal I’d use: Korky 6000BP wax-free$12.49 at AmazonPrice as of Oct 23, 2026, 5:30 AM EDT
Check it on AmazonFind your leak in two questions
Dry everything first. Then answer from what you see over the next flush or two.
The finder asks about timing first because each part of a toilet only holds water at certain times. The supply line and the tank hold water all day. The floor seal under the bowl only sees water for the few seconds a flush takes to pass into the drain.
So a puddle that’s there in the morning before anyone has used the toilet points up, to the tank or the line. A puddle that only shows up after a flush points down, to the seal.
The paper towel test
Five minutes, a roll of paper towels and one flush. Where the towel gets wet first is your answer.
- 1Dry everything
Wipe the floor, the base, the back of the bowl, the tank bottom and the supply line until they’re dry.
- 2Lay the towels
Tuck a ring of paper towel around the base, one under the tank bolts and one wrapped around the supply line.
- 3Wait 15 minutes
Don’t flush yet. Any wet towel now means a leak that doesn’t need a flush: line, valve or tank.
- 4Flush once
Flush, then watch the base for a minute. A towel that wets at the floor only now points to the floor seal.
- 5Check the tank
Feel the outside of the tank. Cold and beaded all over means sweat, not a leak.
- 6Mark the spot
Note which towel got wet first. Water runs downhill, so the first wet spot is closest to the source.
| First wet towel | Before or after a flush | Points to |
|---|---|---|
| Around the supply line | Before | Supply line, its nuts or the shutoff valve |
| Under a tank bolt | Before | Tank bolt washers or the tank-to-bowl gasket |
| At the floor, front or sides | After | Floor seal (wax ring) or loose floor bolts |
| At the floor, back only | Before | Water running down from the tank or line |
| Everywhere, tank cold and wet | Either | Condensation (sweat) |
A drop of food coloring helps when you can’t tell tank water from bowl water. Put a few drops in the tank, as the EPA suggests for leak checks, and don’t flush. Colored water on the outside of the bowl means it came from the tank. Clear water at the floor after a flush points back to the seal. Flush when you’re done so the dye doesn’t stain.
The five causes, side by side
Most leaks at the base are one of these. The fix ranges from a quarter turn of a nut to pulling the toilet.
| Cause | Tell-tale sign | Fix | Toilet stays in place? |
|---|---|---|---|
| Floor seal (wax ring) | Water at the floor only after a flush; may smell of sewer | Pull the toilet and replace the seal | No |
| Loose floor bolts | Toilet rocks; water after a flush | Snug the nuts, shim, then reseal if it still leaks | Yes, unless the seal is broken |
| Tank bolts or gasket | Water down the back of the bowl, flush or not | Snug the tank nuts; replace the gasket kit | Yes; the tank comes off |
| Supply line or valve | Drip at the wall side, all the time | Tighten or replace the line or valve | Yes |
| Condensation | Cold, beaded tank in humid weather | Cut humidity or warm the tank water | Yes |
American Standard’s own help page starts the same way: find where the water is coming from before you buy anything. It also gives the one cause that no part can fix. A visible crack in the base or the tank means the toilet or tank needs to be replaced.
My call: start with the cheap checks that don’t move the toilet. Tighten, look and test for ten minutes before you pull the bowl and lose a seal you didn’t need to replace.
When it’s the floor seal under the toilet
The seal sits between the bowl’s outlet and the drain flange in the floor. There’s no way to replace it without lifting the toilet.
American Standard says that if you look over the base and tank and see no cracks, a leak at the base suggests the wax ring needs to be replaced. Signs that point there: water only after a flush, a stain or soft spot in the floor around the base, and a sewer smell, since the same seal keeps drain gas in.
Seals usually fail for one of two reasons. The toilet rocked and broke the wax, or the flange sits too low or too high for the ring that’s on it. That’s why the seal you buy should match where your flange sits.
| Seal | Flange it fits, per the maker | Can you reset the toilet? | Warranty |
|---|---|---|---|
| Korky 6000BP wax-free | Above, even with and below the floor; 3 or 4 in. drains | Yes, several tries | 10 years |
| Fluidmaster 7530 Better Than Wax | Any flange; uneven floors and tile over recessed flanges; 3 or 4 in. | Yes | 10 years |
| Fluidmaster 7510 standard wax | Even with or above the floor; 3 or 4 in. | No, use a new ring | None listed |
| Fluidmaster 7513 extra-thick wax | Even with or below the floor | No, use a new ring | None listed |
| Fluidmaster 7512 reinforced wax kit | Even with or above the floor; bolts included | No, use a new ring | 10 years |
Korky’s point about wax is the practical one: a wax ring can be ruined if the toilet isn’t set right the first time, and it has to be replaced. Its rubber seal can be lifted and set again. Fluidmaster says the same of its 7530 and adds that plunging won’t cause it to leak.
My call: for a homeowner doing this once, a wax-free seal takes the pressure off the set. If you’re used to wax and the flange sits right, a good ring still works.
- 1Shut off and empty
Close the shutoff valve, flush, and sponge out what’s left in the tank and bowl.
- 2Lift the toilet
Take off the supply line and the floor nuts, rock the bowl gently to break the seal, and lift it straight up.
- 3Clean both faces
Fluidmaster’s first step: clean the old wax and debris off the bottom of the bowl and the floor flange.
- 4Check the flange
Look for cracks and note its height against the finished floor. That picks your seal.
- 5New bolts and seal
Fit new floor bolts with their retainer washers, then the seal. Fluidmaster puts a wax ring on the bowl outlet, flange pointing away from the bowl.
- 6Set and snug
Lower the bowl straight down, press with your weight, then snug the nuts. Fluidmaster says don’t over-tighten, or the bowl can break.
Kohler adds one detail people miss: if the wax ring has a plastic cone, the tapered end goes down into the floor flange. Fluidmaster’s last steps cut the bolt about 1/4 in. above the nut and snap on the caps.
The full job is in how to replace a toilet wax ring. If the flange sits below the floor, read toilet flange too low before you buy a seal, and the closet flange guide if it’s cracked.
A toilet that rocks breaks its own seal
If the bowl moves when you sit, fix that first. A new seal under a rocking toilet will fail the same way.
| What you find | What to do | Watch out for |
|---|---|---|
| Floor nuts loose | Snug each nut a little at a time, side to side | Over-tightening cracks the base |
| Nuts tight, bowl still rocks | Slide shims under the low side until it’s solid | Trim shims flush before caulking |
| Rocks and leaked after a flush | Snug and shim, then dry-test; reseal if it still leaks | The old seal may already be broken |
| Floor feels soft by the base | Stop; the subfloor may be damaged | A new seal won’t hold on a soft floor |
Fluidmaster’s wax steps say it plainly in capitals: do not over-tighten the bolt nuts. Porcelain cracks before a steel bolt bends, so stop at firm, not tight.
Shims fill the gap a nut can’t. The Wobble Wedge 5030 pack has 30 clear wedges about 1/4 in. thick at the tall end that stack and trim with scissors. My call: shim before you caulk the base, and leave the back of the caulk line open so a future leak shows instead of hiding. More on this in the wobbly toilet guide.
When water runs down from the tank
On a two-piece toilet, the tank sits on a sponge gasket and two or three bolts. Any of those can drip to the floor.
- 1Take the lid off
American Standard starts by laying a level across the top of the tank.
- 2Find the nuts
They’re under the back of the bowl, one on each tank bolt.
- 3Quarter turns
Tighten each nut a quarter turn at a time, alternating between them, so the china doesn’t crack.
- 4Turn the nut only
Hold the bolt head still; American Standard says to turn only the nut.
- 5Check for movement
When it’s right, the tank doesn’t move on the bowl.
- 6Still leaking?
Replace the tank-to-bowl gasket and bolts as a kit.
| Order, top to bottom | Part | Note from Fluidmaster |
|---|---|---|
| 1 | Bolt head | Inside the tank |
| 2 | Rubber washer | Directly under the bolt head; never a metal washer here |
| 3 | Toilet tank | — |
| 4 | Metal washer and thin nut | Optional, only if there’s a gap between tank and bowl |
| 5 | Toilet bowl | — |
| 6 | Rubber washer, metal washer, nut | Under the bowl |
Fluidmaster’s warning about the washers is the one I’d tape inside the tank lid: a metal washer directly under the bolt head inside the tank will cause a leak. The rubber washer seals the bolt hole; metal there just presses on it unevenly.
The Korky 464BP kit fits most 2 in. two-piece tanks. Korky gives its gasket as 2-1/8 in. inside, 3-1/2 in. outside and 1-1/4 in. thick, with stainless hardware. Kohler three-bolt tanks and some other brands need their own kit; the tank-to-bowl gasket by brand guide shows which.
When the drip is at the supply line
A wet spot on the wall side that’s there before anyone flushes usually comes from the line or one of its two nuts.
| Check | What American Standard or Fluidmaster says | Fix |
|---|---|---|
| The line itself | Check the supply tube for cracks | Replace the line if it’s cracked |
| Nut at the tank | Make sure the supply nut is tightened completely | Hand-tight plastic nuts; Click Seal clicks when sealed |
| Fill valve nut | The nut that holds the fill valve in the tank must be tight | Snug it; replace the fill valve if it still weeps |
| Nut at the valve | 1/2 turn past hand-tight for the metal nut | Snug just enough to stop a leak |
| Shutoff valve stem | Drips at the handle, not the nut | Replace the valve |
Fluidmaster’s Click Seal B1T12CS is a 12 in. braided stainless line with a 7/8 in. ballcock end and a 3/8 in. compression end. The plastic nut clicks at its set torque (Fluidmaster lists 15 to 20 in-lb), so it stops at its set torque instead of being cranked too tight. Fluidmaster rates the line to 1,500 psi burst.
Measure from the valve to the fill valve before you buy; toilet supply line size shows how. If the line is old, rubber or kinked, replace it even if the leak turns out to be somewhere else. It’s the part most likely to fail all at once.
When it isn’t a seal at all
Two causes look like a leak at the base: water condensing on a cold tank, and a crack in the china.
| Sign | Sweat (condensation) | Crack |
|---|---|---|
| When | Humid days, after lots of flushing with cold water | Any time; often after a bump or over-tightening |
| Where | Beads all over the outside of the tank and bowl | One line of water from one spot |
| Tank feels | Cold and wet everywhere | Normal; wet at the crack |
| After a dry-off | Comes back slowly as a film | Comes back as a trickle or drip |
| Fix | Lower the humidity or warm the tank | Replace the tank or bowl |
Sweat is the easiest to rule out. If the tank is beaded from the lid down and the bathroom is humid, run the fan and see if it dries. The ways to stop it for good are in why toilets sweat.
Cracks are the one cause with no part to buy. American Standard says a noticeable crack in the base or tank means it needs to be replaced. Hairline cracks can hide under the rim, so dry it and run a flashlight along the base. The cost to replace a toilet covers what that runs.
The parts for each cause
Buy the part your test points to, not all four. I’ve used every part in this kit.
Korky 464BP tank kit
$6.19 at Amazon
Check it on AmazonPrice as of Oct 23, 2026, 5:30 AM EDT · low stock then
Fluidmaster Click Seal line
$8.33 at Amazon
Check it on AmazonPrice as of Oct 23, 2026, 5:30 AM EDT · low stock then
Wobble Wedge shims
$14.99 at Amazon
Check it on AmazonPrice as of Oct 23, 2026, 5:30 AM EDT
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon.com at the time of purchase will apply to the purchase of this product.
| Part | Key specs | Pick it if | Skip it if |
|---|---|---|---|
| Korky 6000BP | Red rubber seal with foam rings for above, even and below-floor flanges; 3 or 4 in. drains; bolts, washers and nuts; made in USA; 10-year warranty | Water shows up at the floor after a flush and you’re pulling the toilet. | The flange is cracked or broken. Fix the flange first. |
| Korky 464BP | Sponge gasket 2-1/8 in. ID × 3-1/2 in. OD × 1-1/4 in.; 3 stainless bolts with washers and nuts; 5-year warranty | Water runs down the back of the bowl and snugging the tank nuts didn’t stop it. | You have a Kohler three-bolt tank or a one-piece toilet. |
| Fluidmaster B1T12CS | 12 in. braided stainless over a polymer core; 7/8 in. ballcock × 3/8 in. compression; 1,500 psi burst; 5-year warranty | The line is cracked, kinked or old, or the nut at the tank weeps. | Your valve is more than 12 in. from the fill valve. Measure first. |
| Wobble Wedge 5030 | 30 clear flexible wedges, 1.92 × 1.11 × 0.25 in., stackable, trim with scissors; made in USA | The bowl rocks with the floor nuts snug. | The floor is soft or the flange is broken. Shims won’t fix that. |
Need a second seal choice? The Fluidmaster 7530 is Fluidmaster’s wax-free seal, with a stackable spacer and brass bolts; Fluidmaster says it seals on uneven floors and over tile with a recessed flange. For a side-by-side of every seal, see the toilet wax ring guide.
Tools you likely have: an adjustable wrench, a putty knife for old wax, a bucket and sponge, and a hacksaw blade or the bolt’s own snap-off groove to cut long floor bolts.
Is a toilet leaking at the base an emergency?
Usually it’s not a flood. But a slow leak at the floor does its damage where you can’t see it.
| What you see | My call | Do this now |
|---|---|---|
| A little water after flushes, floor firm | Fix it this week | Use another toilet if you can; dry the floor |
| Water there all the time, steady drip | Fix it today | Close the shutoff valve between uses |
| Sewer smell at the base | Fix it today | The seal is open to the drain; stop using it |
| Floor soft, tiles loose, or a stain on the ceiling below | Act now | Shut off the toilet and call a plumber |
| Line burst or spraying | Emergency | Close the shutoff valve or the main |
The reason to move fast is the floor. Water that gets under vinyl or tile soaks the subfloor around the flange, and a soft subfloor means the next seal won’t hold either. If there’s a room below, look at its ceiling under the toilet for a stain.
Know where your shutoff valve is before you need it. It’s the oval or round handle on the wall or floor behind the toilet; turn it clockwise to close.
When to call a plumber
| What you find | Why it’s a pro job |
|---|---|
| Flange cracked, broken or rusted through | The flange has to be repaired or replaced at the drain |
| Flange well below the finished floor | It needs an extender or a new flange, not just a thicker seal |
| Soft or rotten subfloor | The floor must be repaired before the toilet goes back |
| Shutoff valve won’t close or leaks at the stem | Replacing it may mean shutting off the house |
| Leak keeps coming back after a new seal | Something under the toilet is wrong; it needs eyes on it |
Pulling and resetting a toilet is a fair job for a handy homeowner. The rest of that list is where I’d stop. For a price range in your area, try the plumbing cost estimator.
Questions people ask
Why is my toilet leaking at the base?
Most often the floor seal (wax ring) under the bowl has failed, or the floor bolts are loose and the toilet rocks. Water from the tank joint or the supply line can also run down and pool at the base, and a cold tank can sweat.
How do I know if my wax ring is leaking?
Water shows up at the floor around the front or sides only during or right after a flush, and the tank and line stay dry. A sewer smell or a soft spot in the floor at the base are other signs.
Is a toilet leaking at the base an emergency?
Usually not a flood, but don’t wait. Fix it within days, and stop using it today if you smell sewage, the floor is soft or there’s a stain on the ceiling below.
Why does my toilet leak at the base only when I flush?
That points to the floor seal or loose floor bolts. The seal only carries water for the few seconds a flush passes into the drain.
Why is my toilet leaking at the base without flushing?
A leak with no flush comes from something that always holds water: the supply line, its nuts, the shutoff valve or the tank-to-bowl joint. The water runs down and pools at the base.
Can I fix a toilet leaking at the base without removing it?
Sometimes. Snugging floor bolts, shimming, tightening tank nuts and replacing a supply line are all done with the toilet in place. A failed floor seal needs the toilet lifted.
Should I caulk around the base of the toilet?
Caulk keeps mop water out and helps hold the bowl, but it won’t fix a leak. My call: leave a gap at the back so a future leak shows instead of hiding under the floor.
How tight should toilet bolts be?
Firm, not tight. Fluidmaster says don’t over-tighten floor bolt nuts or the bowl can break, and American Standard tightens tank nuts a quarter turn at a time, alternating sides.
How I put this together
Why trust me
I’m Isaac Daniels, a licensed journeyman plumber in Georgia (license #JP507711). I’ve used every part in the kit. The repair steps and limits come from American Standard, Fluidmaster, Korky and Kohler help pages and product pages, read on Oct 22, 2026. My own opinions are marked “My call.”
How I pick
- One part per cause, from brands that publish specs and warranty terms.
- New and in stock on Amazon on Oct 22, 2026. No look-alike parts.
- No scores: a floor seal, a tank gasket kit, a supply line and shims do different jobs, so they’re listed as a kit.
- Prices come from Amazon’s API with the time they were read.
Sources
- American Standard Knowledge Base, “What should I do if my toilet leaks water onto the floor?” (faq.americanstandard-us.com, read Oct 22, 2026): cracks, wax ring, supply and fill valve nuts, tank nut quarter turns.
- Fluidmaster, “How to use wax when installing a toilet bowl” (fluidmaster.com, read Oct 22, 2026): cleaning, bolts, ring orientation, no over-tightening, cutting bolts.
- Fluidmaster, “Installing / resolving leaks at the tank bolts” (read Oct 22, 2026): washer order and the metal washer warning.
- Fluidmaster, “Instructions / FAQs on Click Seal Supply Lines” (read Oct 22, 2026): 1/2 turn past hand-tight, 1,500 psi burst, 15–20 in-lb torque.
- Fluidmaster retail catalog and wax and wax-free seal product pages (7510, 7512, 7513, 7530), and its Limited Express Warranty table (read Oct 22, 2026).
- Korky, 6000 WaxFREE Seal Kit and 464 tank-to-bowl kit product pages (korky.com, read Oct 22, 2026).
- Kohler Assist, “Installing a Toilet Wax Ring” (assist.kohler.com, read Oct 22, 2026): plastic cone tapered end down.
- U.S. EPA WaterSense, Fix a Leak Week page (epa.gov, read Oct 22, 2026): food coloring in the tank to find toilet leaks.
- Part details for the Korky 6000BP and 464BP, Fluidmaster B1T12CS and 7530, and Wobble Wedge 5030, read from Amazon’s product data on Oct 22, 2026.