toilet tank

Toilet Leaking From Tank Bolts? Here Is How To Fix It

Tank bolts are a vital component of your toilet, but sometimes they can be the source of a leak. Leaky toilets are a huge problem, especially if you’re worried about your water bill.

There are several different things that can cause toilet tank bolts to leak. The steps to fix the problem will depend on the issue.

Most people will be able to solve their leak problem through DIY steps. But if you’re in doubt, you can always call a plumber for a second opinion.

toilet tank bowl bolts

How Do I Stop My Toilet Tank Bolts From Leaking?

The majority of toilet designs include bolts that secure the tank to the bowl. The head of the bolt will be separated from the tank wall by a rubber or metal washer.

Sometimes there will also be washers installed between the tank and bowl themselves. This helps to add a higher level of security and keep the toilet bowl from moving when you use it.

Tank bolts are generally made from metal. This means that they can be subject to corrosion over time, especially if you’re dealing with hard water.

Here are the main steps to take care of the issue.

1. Find out where the leak is coming from.

You might already know that the issue is related to the tank bolts. But now it’s time to figure out exactly why there are problems.

Do the bolts look like they’re too loose? You might know that the bolts are loose if you often feel the toilet bowl move as you sit on it.

But keep in mind that tightening the bolts too much can cause your porcelain to crack.

Do you see any corrosion? Corroded bolts should be replaced with a new model.

Similarly, you should get replacements for any corroded nuts or washers. These components will corrode more quickly if you have a very humid bathroom.

You might also find that the leak isn’t coming from the bolts at all. Look for puddles of water on the floor.

Then look at the spot where the bowl and tank connect. Is water coming from there?

2. Empty the tank and turn off your water.

This step is pretty straightforward. When you’re doing work on any kind of leak, you want to make sure that the water is turned off.

That can help save you from major mishaps down the road.

Just follow these steps:

  • Find the supply valve at the back of the toilet.
  • Loosen the valve with a wrench.
  • Turn it about a half-inch clockwise to shut it off.
  • Flush the toilet, thereby emptying the tank.

3. Remove the tank and bolts.

Now that the tank is empty, you can use a wrench to unscrew the nuts connecting the tank and bowl. You might also be able to unscrew them using just your hand.

If the pieces are too corroded to move with your hand, try grabbing them with a pair of pliers instead. You can tap the nut with the pliers to break up the rust, too.

Lift the tank and put it on the closed toilet lid.

4. Replace the necessary pieces.

There’s a good chance that the leak is being caused by corrosion. Make sure you have the proper hardware to replace your tank bolts.

You can usually get all of the pieces in a tank kit, which will also include instructions.

Some kits come with extra washers and nuts. It’s a good idea to use rubber washers rather than metal ones, as metal can cause damage to the porcelain if the bolt is tightened too much.

Each toilet will have slightly different instructions for replacing the bolts. Just follow the guide.

5. Put the toilet tank back.

After everything is in place, you should put the tank back. Then secure the bolts using the nuts and washers.

It’s important not to tighten them too much, as doing so might cause your toilet bowl to crack.

If The Toilet Is Leaking From Tank Bolts When Flushed

toilet leaking from tank bolts

Sometimes the leak will happen when the toilet is flushed. It’s important for you to do a full inspection so that you can find the source of the leak.

When you discover that the issue is the tank bolts, you should follow all of the same steps listed above.

If you’ve completed all of the above steps, and you’re still having a problem with your toilet leaking, then you should get in contact with a plumber. They might be able to determine where the big issue is.

Can You Use Plumber’s Putty On Toilet Tank Bolts?

It’s not a good idea to use plumber’s putty on a toilet tank bolt. You might be tempted because the material is supposed to be a good sealant.

But it isn’t built for this purpose. It won’t give you the kind of seal you need, and it can even impede the rubber gasket from sealing properly.

Overall, this is a situation in which plumber’s putty is likely to harm rather than help.

How Do You Tighten A Toilet Tank Bolt?

tighten a tank bolt

Tightening the toilet tank bolts should be simple as long as you have a screwdriver and adjustable wrench.

You should have a rubber washer placed between the porcelain and the bolt. Then you should screw the nuts onto the bolts by hand.

Just twist them with your fingers.

You can then use the wrench to turn each nut one-quarter of the way around. There’s no need to make the bolt extremely tight.


There are several reasons that a toilet might start leaking from its tank bolts. Some of the solutions are simple, while others require a little more work.

You’ll need to find out the reason for the leak and then adjust or replace the bolts.

In most cases, you should be able to fix the problem yourself. But if you’re having persistent issues, it’s important to contact a professional who can handle the situation.