Quick answer
To fix a leaking toilet base, first shut off the water supply and remove the tank lid. Tighten the bolts at the base of the toilet with a wrench. If the leak persists, replace the wax ring by removing the toilet, cleaning the flange, and reseating the toilet with a new wax ring.
Confirm the symptom
- Water pooling around the base of the toilet
- Dampness or mold under the toilet
- Toilet wobbling when sat on
Tools and prep
- Adjustable wrench
- Plumber's putty or wax ring
- Plastic putty knife
- Towel or rags
- Rubber gloves
- Shut off water supply to the toilet
- Turn off electricity to the bathroom if using power tools
Step-by-step troubleshooting
- Shut Off Water SupplyDo: Turn the shut-off valve clockwise to stop water flow to the toilet.Observe: Water stops flowing into the tank and bowl.Means: The toilet is isolated from water supply.Next: Drain Tank and Bowl
- Drain Tank and BowlDo: Flush the toilet and hold the handle to drain as much water as possible. Use a sponge or towel to soak up remaining water.Observe: Tank and bowl are mostly dry.Means: Water is removed to prevent spills during repair.Next: Remove Tank Lid
- Remove Tank LidDo: Lift the tank lid and set it aside on a soft surface to avoid damage.Observe: Tank lid is off and tank is accessible.Means: Access to tank components is gained.Next: Tighten Base Bolts
- Tighten Base BoltsDo: Use an adjustable wrench to tighten the nuts on the bolts at the base of the toilet. Do not overtighten.Observe: Bolts are snug and the toilet is stable.Means: Loose bolts may have caused the leak.Next: Check for Leaks
- Check for LeaksDo: Turn the water supply back on and let the tank fill. Check the base for any signs of water leakage.Observe: No water is leaking from the base.Means: Leak was due to loose bolts.Next: Replace Wax Ring if Needed
- Replace Wax Ring if NeededDo: If the leak continues, shut off the water again and remove the toilet by loosening the base bolts and lifting it off the flange. Clean the flange and toilet base, then install a new wax ring before reseating the toilet.Observe: Toilet is reseated with a new wax ring and no leaks.Means: Old or damaged wax ring was causing the leak.Next: Final Check
Common causes
| Cause | Likelihood | Difficulty | Part often needed |
|---|---|---|---|
| Loose Bolts Bolts at the base of the toilet can become loose over time, causing the toilet to wobble and leak. | Common | Easy | None |
| Damaged Wax Ring The wax ring can deteriorate or become misaligned, creating a gap that allows water to leak. | Common | Easy–Medium | Wax Ring |
| Cracked Toilet Base Cracks in the porcelain at the base of the toilet can allow water to escape. | Sometimes | Hard | New Toilet |
| Improper Installation If the toilet was not installed correctly, it may not form a proper seal with the flange, leading to leaks. | Sometimes | Medium | Wax Ring |
| Worn Flange The flange (the pipe the toilet sits on) can become damaged or corroded, preventing a proper seal. | Sometimes | Medium | Toilet Flange Repair Kit |
| High Water Pressure Excessively high water pressure can stress the toilet's seals and cause leaks. | Rare | Medium | Pressure Regulator |
Parts matching
Common parts needed for a leaking toilet base include:
- Wax Ring – Creates a watertight seal between the toilet and flange
- Toilet Flange Repair Kit – Repairs or replaces a damaged flange
- Plumber's Putty – Alternative to wax rings for sealing
- New Toilet – Required if the base is cracked or severely damaged
- Toilet Bolts – Ensures the toilet is securely fastened to the floor
Always use a high-quality wax ring or plumber's putty for the best seal and to prevent future leaks.
When to call a professional
- Leak persists after replacing the wax ring and tightening bolts
- Toilet base is cracked or damaged beyond repair
- Flange is severely corroded or damaged
- You are unsure about removing or reseating the toilet
- Water damage has spread to the subfloor or surrounding area
FAQ
Can I use silicone instead of a wax ring?
Silicone can be used as an alternative to a wax ring, but it is not as effective for a watertight seal. A wax ring is recommended for the best results.
How often should I check my toilet for leaks?
Check your toilet for leaks at least once a year, or if you notice any signs of water damage or a foul odor.
Why does my toilet leak only when I flush it?
A leak that occurs only during flushing may be due to a loose connection in the tank or a faulty flapper. Check the tank components and ensure all connections are tight.
Can a wobbly toilet cause leaks?
Yes, a wobbly toilet can cause leaks by creating gaps between the toilet and the flange. Tighten the base bolts to stabilize the toilet.