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Why Is My Toilet Leaking? A New York Plumber Explains

April 14, 2021


A leaking toilet is an unsightly and potentially expensive issue. If you’ve noticed that water is pooling around your toilet or if you hear a persistent trickling sound coming from your toilet, you’re right to be concerned.

In this blog, we’ll help you identify the problem quickly so that you can prevent expensive water damage and unnecessarily high water bills.

The first step to determining why your toilet is leaking is to pinpoint the source of the leak:

  • If water is leaking from the tank and into the bowl (but not spilling onto the floor), it’s likely that your flapper is misaligned or faulty and needs to be replaced.
  • If the leak seems to be coming from behind the toilet, it’s likely that your toilet shutoff valve is the culprit.
  • If water is leaking from the tank and pooling onto the floor, it’s likely that your toilet tank is cracked.
  • If the leak seems to be coming from between the toilet tank and bowl and typically only leaks after flushing, it’s likely that the rubber gasket between the tank and the bowl needs to be replaced.

We’ll explore each of these leaking toilet scenarios and explain what you should do in each instance.


Need a professional plumber to handle your leaking toilet? Schedule with Ranshaw! We have 50+ years of experience helping customers throughout Queens with toilet and plumbing issues, large and small, and we can help you too

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If water is leaking from the tank...

...either the toilet flapper is the issue or the tank is cracked and needs to be replaced.

If water is dripping from the tank and onto the floor, the issue is most likely that the tank itself is cracked. If the tank is cracked, you’ll need to hire a professional to replace the tank.

If water is leaking from the tank and into the bowl—and no water is escaping and dripping onto the floor—the issue is likely a faulty flapper.

Your toilet flapper is a small device located in the tank that controls the volume of water released to the bowl when you flush the toilet.

The flapper acts as a seal in normal operation. So, if the flapper is not set properly and has somehow become misaligned, it can cause water to slowly leak from the tank and into the bowl. Sometimes the flapper can crack or wear out, which can also cause a slow, persistent leak into the bowl.

While water leaking from the tank and into the bowl might seem like a minor inconvenience (a persistent trickling/gurgling noise), if no action is taken, this leak can waste over 200 gallons of water a day, which is both wasteful and expensive.

What to do:

Check your flapper by removing the lid of the toilet tank and checking to see if the flapper seal is stuck, misaligned or cracked. If the flapper is stuck or misaligned, try readjusting the device yourself.

However, if the flapper is cracked and needs to be replaced, consider hiring a plumber to get this job done correctly and quickly.

If the water seems to be coming from behind the toilet…

...the toilet shutoff valve might be the issue.

Most toilets have a shutoff valve located behind the toilet. These valves often go years without being turned on or off. This level of inactivity can cause mineral deposits which might result in the valve springing a leak.

What to do:

If your toilet shutoff valve is leaking, use pliers to try and tighten the valve. Don’t tighten the valve too hard, 1/8th of a turn is sufficient to try and stop a leak. Overtightening the valve can worsen the problem.

If this doesn’t stop the leak, you likely have a valve that needs to be replaced. If your valve needs replacing, trust a professional plumber to complete the job to ensure it is done correctly and safely.

If the leak seems to be occurring between the tank and the bowl…

...it’s likely that the gasket between the tank and bowl needs to be replaced. If this is the issue, you likely will only see water leaking when the toilet is flushed.

All toilets have a seal (aka gasket) that prevents water from leaking between the two separate pieces (the tank and bowl are typically two separate pieces on a toilet).

Sometimes this type of leak can be hard to detect since the water will typically only leak at the time of a flush and, depending on the shape of the toilet, this water may directly fall into the bowl and go unnoticed (versus pooling on the floor).

What to do:

If you notice water leaking between the tank and the bowl and suspect a worn out gasket/seal, it’s best to hire a professional plumber to replace the gasket.

While the most likely culprit in these situations is a worn out gasket, you could also have worn out washers on your tank-to-bowl bolts. A professional plumber will be able to inspect your toilet, correctly diagnose the issue and then solve the problem quickly.

Need a plumber you can trust for your leaky toilet?

Trust the experienced plumbers at Ranshaw Plumbing & Heating. We’ve provided honest and skilled plumbing services in the Queens and New York City area for more than 50 years and we have the reviews and reputation to prove it.

If you’re in need of a plumber who can quickly and correctly diagnose your leaking toilet, the first time around, just call Ranshaw.

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