Why is My Toilet Overflowing? Common Causes and How to Fix

There’s nothing like the panic of seeing your toilet bowl filling slowly and keep rising. A toilet overflowing can be messy, stressful, and costly if not handled quickly. Luckily, with a little know-how, you can often stop the toilet overflow and prevent it from happening again.

Immediate Steps to Take When Your Toilet Is Overflowing

Before you reach for the plunger, here’s what to do right away when your toilet is overfilling:

• Shut off the water supply. Look for the shutoff valve behind or beneath the toilet and turn it clockwise.
• Remove the tank lid. Lift the float to stop water from entering the bowl.
• Don’t flush again. That’ll just add more water to the bowl and worsen the mess.
• Contain any overflow. Use towels or a wet/dry vacuum to soak up standing water quickly to avoid damage.

Once things are under control, it’s time to figure out what’s causing the problem and fix it.

What Causes a Toilet Bowl to Overflow?

The water stopped flowing, but what caused your toilet to overfill in the first place? The most common culprit is a clog. It could be from excess toilet paper or common objects that should never be flushed, like wipes, feminine hygiene products, or toys.

Other causes include:

• A blocked drain line
• A slow drain due to buildup
• A poorly fitted or damaged toilet flange

Why Is My Toilet Overflowing But Not Clogged?

If there’s no clog but your toilet is overflowing, the issue may be mechanical. A running toilet or a faulty fill valve can cause water to rise uncontrollably. The tank may not be shutting off properly, sending water into the overflow tube even when the bowl doesn’t need it. Learn how to fix a running toilet to resolve this kind of overflow.

Another possibility? The main sewer line is backed up. In that case, you’ll likely notice drainage issues in other fixtures like sinks or showers. That’s a job for a plumber.

How to Fix an Overflowing Toilet (Step-by-Step)

If your toilet overflows when flushed, follow these steps:

1. Turn off the water valve. Prevent more water from flowing into the tank.
2. Use a plunger. A flange plunger works best. Make sure you get a good seal and plunge in short, forceful bursts.
3. Try a drain auger. If plunging doesn’t work, a toilet auger can help reach deeper clogs.
4. Use an eco-friendly drain solution. Just be sure to never mix commercial chemical products.
5. Test the flush. Once the water goes down and the toilet seems to be working, try a test flush. If the bowl refills properly and drains normally, you're good to go.

How do you unclog a toilet when the water is high? Consider using a bucket to dump out some of the water, then try the steps above.

How to Prevent Future Toilet Overflows: Tips and Maintenance

You should always be following our plumbing tips to avoid toilet clogs. But here are a few specific ways to prevent an overflow in your toilet bowl:

• Use less toilet paper. Excess paper is a top cause of clogs.
• Flush only waste and paper. Even products labeled "flushable" aren’t always safe. Read this guide on Charmin flushability to learn more.
• Watch for signs of trouble. Slow drains or gurgling sounds can signal a clog forming.
• Maintain your toilet hardware. Replace worn-out flappers, fill valves, and tank components as needed.
• Schedule regular inspections. Older systems may need professional maintenance to prevent hidden issues.

When to Call a Professional Plumber

If plunging doesn’t work, or the toilet continues overflowing or overfilling after multiple fixes, it’s time to call in a pro. A plumber can:

• Identify hidden clogs or sewer issues.
• Replace faulty fill valves or broken flanges.
• Recommend long-term solutions if you have frequent backups.

Need expert help now? Roto-Rooter’s licensed plumbers are available 24/7 to tackle toilet overflows, clogs, and more. Whether your toilet overflows when flushed or you’re experiencing toilet flooding from the tank, we’ve got the tools and experience to fix the problem fast.

Don’t wait until the next overflow. Call Roto-Rooter today for professional toilet repair and plumbing support.