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Is Your Toilet Leaking From the Tank Bolts? Here’s How to Fix It

A toilet tank bolt leak is a pretty easy problem to fix if you know what to do. However, if you’re a homeowner who’s fairly unskilled, then you’ll want to take advantage of the information below. By fixing the problem yourself, you’ll dodge an expensive service bill.

A toilet that leaks from its tank bolts is usually leaking because of damaged, misaligned or even cracked washers or bolts. You have to either tighten the bolts or replace them.

Generally, two-piece toilets have a set of bolts that attach the tank to the bowl. These bolts travel through a hole at the bottom of the tank and then run through matching holes located in the bowl.

With most models, rubber washers sit between the bolt head and the inside of the tank. Washers or spacers also sit between the tank and the bowl, and a washer made out of a metal, rubber or plastic is placed on the bolt between the bowl and the nut. This secures the tank into place and prevents it from moving.

To stop the leaking, these bolts or washers will more than likely need to be replaced. In order to complete these repairs, you’re going to need an adjustable wrench and a set of bolts, nuts, and washers. These typically come together in a kit.

Start by locating the water supply valve, turn it completely off and then flush your toilet just one time.

If there is any that won’t drain, which shouldn’t be more than an inch, use a large cleaning sponge to soak the rest up.

Once your water has been turned off, follow the steps below:

  1.  Remove all the necessary bolts, washers and nuts from both the inside of the tank and below the bowl.
  2. Replace any faulty spacers, bolts and washers between the tank and the bowl.
  3. Now take the tank and gently place it onto the bowl.
  4. Make sure the holes are aligned.
  5. Slip a bolt with a washer into each of the aligned holes.
  6. Continue to hold the tank in the right position and put a washer on the bolt and under the bowl.
  7. Tighten the nut. When you tighten the nut, start by tightening it with your hand, and then gently tighten it more with a tool. It’s essential to be careful, so you don’t crack the porcelain. Give the nuts a snug fitting.
  8. Turn back on your water and give your toilet a test flush.
  9. Check for leaks.

If your tank bolts are damaged, you might need an extra tool to remove them.

If you have a toilet tank bolt that is damaged or corroded, you can just cut off the nut. This is easy to do with a mini hack saw.

Hard water can cause corrosion in your tank bolts. Homeowners who live in areas with particularly hard water can prevent this by using solid brass bolts. If you are using hard water, you can spray your bolts with a rust protector. This just might help extend their life.

If the bolts just spin in circles instead of becoming loose, you’ll need to remove and replace them. To get them off, use a screwdriver on the head of the bolt and your wrench on the nut. Twist the wrench to the left. This should loosen them up.

Replacing the tank to bowl gasket

The tank to bowl gasket beneath the tank can also become damaged. The gasket is located where the tank is connected to the bowl. Remove the old gasket and inspect it. If it looks worn or damaged, you’ll definitely want to replace it.

Related Questions

Why is my tank still leaking after I replaced both the bolts and the washers?

Like mentioned above, the nuts on the bolts might need to be tightened up. Leaks can also occur if the nuts are tightened too much as well. Ideally, they should be snug. Overly tight nuts can also damage the gasket and possibly crack the toilet bowl or the tank.

Do I need to replace the bolts in the back if tightening them stopped the leak?

If the leak has stopped, but the bolts are old or corroded, then yes you should replace them. However, if they’re in fairly good condition, or they were replaced recently, then it’s not necessary. It’s important to remember that leaks can occur when the bolts are not screwed on tight enough.

How do I know what toilet tank bolts to get?

Toilet tank bolts are all universal. That means they all have the same dimensions and can be used to fasten any toilet tank.

Should I use a sealant to stop a toilet tank leak?

Sealants work great as temporary fixes, but they’ll eventually fail. The best fix is to simply replace the bolts, the washers, and the tank to bowl gasket.

Take advantage of these tips when your toilet tank bolts leak and cause you a problem. In the end, by doing the job yourself, you’ll keep more cash in your wallet while giving yourself a sense of accomplishment.

Kevin L. Sharp


Saturday 17th of June 2023

Thank you! This information was helpful, particularly that tank bolts are universal.


Thursday 21st of July 2022

Well, I have done all of the above two times now. The right bolt will not stop leaking. On this particular side, I had to use bolt cutters on after spending a day sawing at it. So it is not exactly a perfect round hole. Can't afford a new toilet.


Wednesday 27th of October 2021

I had wing nuts under my bowl which were difficult to tighten so I replaced them with new rubber washers, stainless steel washers and s/s bolts. Unfortunately, no matter how tight they were, they kept leaking through the bolts. I kept tightening and testing and tightening testing and then after 30 minutes of this, the cistern broke. So a standard rubber washer isn't up to the job, I guess I need to get the ones that are concaved and curve down into the hole.

Marianne Bruegger

Sunday 3rd of October 2021

Hi there, I have been working on this issue for four days, and it still leaks. I did buy new hardware, and it still leaks. My nerves are getting the best of me. Can I use something else to seal the top with something else? Anything so that I can seal it off totally. This American Standard is only 2.5 years old, and I do not want to buy a new one, plus find a Plumber. I am 80 yrs old, even though I can still do a lot of things, I need help!

Dave N

Tuesday 5th of October 2021

@Marianne Bruegger, if you can’t figure it out, try taking a photo of the problem and posting it to Craigslist and ask for bids. Depending on where you live, you may get multiple offers at a very reasonable price.


Thursday 20th of September 2018

Very helpful Mr. Sharp. I love sites like yours as I’m definitely a do DIY’er whenever possible ! Ty.