How to Fix a Toilet Leaking at the Base: Wax Ring Replacement and Flange Repair (2026)

Water at the base of a toilet is one of the more alarming things a homeowner can discover, but it almost always has a single cause — a failed wax ring — and a single repair.

Water at the base of a toilet is one of the more alarming things a homeowner can discover, but it almost always has a single cause — a failed wax ring — and a single repair. This guide covers the full process: draining the toilet, removing it, inspecting and repairing the flange if needed, setting a new wax ring, and resetting the toilet so it stays put.

What You Need

• Toilet wax ring (with horn, for most toilets)
• Toilet flange repair ring (if flange is damaged)
• Toilet closet bolts replacement set (brass, 5/16”)
• Toilet shims (if toilet rocks)
• Adjustable wrench
• Putty knife
• Rubber gloves, old towels, and a bucket
• Sponge for removing standing water
• Hacksaw (sometimes needed to cut old flange bolts)

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Understanding the Leak: Wax Ring vs. Other Sources

Before removing the toilet, confirm the leak is coming from the base rather than from another source.

Signs that point to the wax ring:

• Water appears on the floor during or immediately after flushing
• The water has a slight discoloration or odor (sewage contamination)
• The toilet rocks or moves when you sit on it
• The toilet has not been reseated in many years and the floor finish around the base shows staining

Signs that point to other sources:

• Water appears between flushes or constantly — more likely the supply line, the fill valve, or condensation
• Water is at the back of the toilet base near the supply connection — check the flexible supply line hose
• The tank has visible condensation on the outside — water dripping from the tank exterior can pool at the base and look like a wax ring leak

To confirm: dry the floor thoroughly, flush the toilet, and watch exactly where water appears. If it appears around the perimeter of the toilet base within a few seconds of flushing, you have a wax ring leak.

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Step 1: Shut Off the Water Supply and Drain the Toilet

Turn off the shutoff valve. The oval or football-shaped shutoff valve is on the wall behind the toilet at floor level, connected to the white flexible supply line. Turn it clockwise until it stops. If the valve doesn’t shut off fully (water continues to trickle), close the main water shutoff for the house.

Flush to drain the tank. Hold the flush lever down to drain as much water as possible from the tank and bowl.

Disconnect the supply line. Use your hand or an adjustable wrench to loosen the coupling nut where the supply line connects to the bottom of the tank. Have a towel ready — residual water in the line will drip. Remove the supply line completely and set it aside.

Remove remaining water. Use a sponge to soak up the remaining water in the tank, wringing it into a bucket. Repeat for the bowl — get it as dry as possible to reduce weight and minimize mess when you move the toilet.

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Step 2: Remove the Toilet

Find the flange bolts. At the base of the toilet on each side, there are plastic caps covering the flange nuts. Pry the caps off with a flathead screwdriver to expose the nuts underneath.

Remove the nuts. Use an adjustable wrench or channel-lock pliers to remove both nuts. If the nuts spin freely (the bolt is spinning with it), grip the bolt head with pliers while turning the nut with the wrench. If the bolts are corroded and the nuts won’t break free, spray penetrating oil at the nut/bolt junction and wait a few minutes. As a last resort: cut the bolts off below the nut with a hacksaw or mini reciprocating saw.

Lift the toilet off. With the nuts removed, the toilet is no longer secured to the floor — it’s only resting on the wax ring. Grip the toilet at the bowl sides (not the tank) and lift straight up. The wax will release with a slight sucking sensation. Set the toilet on its side on a tarp or old towels — you’ll need access to the horn at the bottom.

Stuff the drain opening. Immediately stuff an old rag or towels into the exposed drainpipe opening in the floor to block sewer gases from entering the room while you work.

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Step 3: Inspect the Flange

With the toilet out of the way, examine the toilet flange carefully. This is the most critical diagnostic step — installing a new wax ring on a damaged flange will only result in a repeat leak.

A good flange looks like: A complete ring, flush with or slightly above the finished floor surface, with the slots for the flange bolts intact and the ring surface free of large cracks or missing sections.

Common flange problems:

Broken or missing sections: Cast iron flanges are prone to breaking in arcs. PVC flanges can crack. If more than a quarter of the ring is compromised, the wax ring won’t have a complete surface to seal against.

Flange set too low: If the finished floor (tile, vinyl, hardwood) was added over the original floor without raising the flange, the flange may be recessed below the floor surface. A standard wax ring may not bridge this gap reliably — use an extra-thick wax ring or a stacked ring setup.

Broken bolt slots: The T-slots that hold the flange bolts can break, leaving the bolt with nothing to anchor to. The bolt spins instead of staying fixed.

Repairing the flange:

For most broken or cracked flanges, a stainless steel flange repair ring is the correct solution. This is a heavy-gauge ring that screws directly into the subfloor over the damaged flange, providing a new, complete sealing surface. The repair ring has its own T-slots for new closet bolts. This repair works for cast iron, PVC, and ABS flanges and typically costs $10–$25.

For a flange that is too low: use an extra-thick wax ring, or stack two standard wax rings (place the one with the horn closest to the toilet horn, the plain ring on the flange side).

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Step 4: Install New Flange Bolts and the Wax Ring

Remove old wax. Scrape the old wax ring residue off the flange surface and off the horn of the toilet using a putty knife. Get both surfaces as clean as you can — old wax left behind can prevent the new ring from seating correctly.

Install new closet bolts. Slide the new brass T-bolts into the flange slots on each side, positioning them so they are centered and aligned with each other. They should point straight up, parallel to the wall behind the toilet. Some flanges use a locking tab to hold the bolt — if yours has one, engage it so the bolt won’t spin during installation.

Position the wax ring. You can attach the wax ring either to the toilet horn or to the flange — both methods work. Most plumbers prefer attaching it to the toilet horn (wax side facing down toward the flange) because you can see what you’re doing during the lift-and-set step. Press the wax ring firmly onto the horn so it adheres and won’t shift during handling.

Do not compress the wax ring before setting the toilet — the compression is what creates the seal, and it happens once during the toilet set.

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Step 5: Set the Toilet

This is the most critical step. The toilet needs to go down in one smooth, controlled motion — once the wax contacts the flange, you cannot lift the toilet and re-seat it without replacing the wax ring again.

Remove the drain plug. Take the rag out of the drain opening.

Line up the bolt holes. Look at the base of the toilet — there are two holes (one on each side) that align with the flange bolts. With a helper, lift the toilet and position it directly over the flange, aligning the holes with the bolts visually before beginning the descent.

Lower straight down. Lower the toilet straight down onto the flange, feeding the bolts up through the toilet base holes. When the toilet base contacts the floor, press down firmly with your body weight — sit on the toilet if needed — to fully compress the wax ring. The toilet base should contact the floor evenly around its perimeter.

Check for rocking. Rock the toilet gently side to side. If it rocks, identify the high spot and slide plastic toilet shims under the base at the high points. Tap them in with a hammer until the toilet sits completely stable. Trim the protruding shim ends with a utility knife.

Install the nuts and washers. Place the metal washer over each bolt, followed by the plastic cap base, then the nut. Hand-tighten first, then snug with a wrench — alternate sides, tightening a little at a time to compress the base evenly. Stop when the toilet doesn’t move. Do not overtighten — the porcelain base will crack. Snap the decorative caps over the nuts.

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Step 6: Reconnect the Water and Test

Reconnect the supply line. Thread the coupling nut onto the fill valve shank at the bottom of the tank. Hand-tighten, then a quarter turn with pliers — no more.

Turn the water on slowly. Open the shutoff valve gradually. Watch the supply line connection and tank fill valve for drips as water pressure is restored.

Allow the tank to fill, then flush. Watch the floor around the toilet base carefully during and after the flush. Dry the floor first if needed to make any water immediately visible.

Flush several times. A fresh wax ring seal needs a few flushes to confirm. No water on the floor after 5 flushes = successful repair.

Apply caulk at the base (optional). Many plumbers caulk the perimeter of the toilet base to the floor after confirming the repair. Leave a small gap at the back of the toilet uncaulked — if the wax ring ever fails again, water can escape at the back rather than pooling invisibly under the base and rotting the subfloor before you notice it.

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When to Call a Plumber

Most wax ring replacements are straightforward DIY repairs. Call a licensed plumber when:

• The flange is broken below the floor level and requires pipe work to repair or replace
• The subfloor is soft, spongy, or visibly rotted — structural subfloor repair is needed before the toilet can be reset
• The drain pipe itself is damaged or disconnected inside the floor
• You cannot stop the water flow to the toilet (shut off valve is stuck and the main is inaccessible)

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Preventing Future Leaks

A properly set wax ring lasts 20–30 years under normal conditions. To protect the seal:

• Don’t allow the toilet to rock. If it develops a wobble, shim it immediately rather than letting it work the wax.
• Don’t apply excessive weight or side force to the toilet (standing on the rim, leaning heavily on one side).
• During any bathroom remodel that adds flooring height: raise the flange with a flange extension to maintain the correct height relationship before resetting the toilet.

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Related Reading

• How to Fix a Running Toilet — fill valve and flapper replacement
• How to Install a Toilet — full toilet replacement from scratch
• How to Unclog a Drain — drain clearing techniques for bathroom fixtures