If your toilet tank is leaking from the bolts, it’s likely due to corroded rubber washers securing the toilet tank bolts. In order to fix this, turn off the water to your toilet, flush the tank to empty it, and then remove the tank. Once the tank is separate from the toilet bowl, replace the rubber gasket on the underside of the tank. Next, you can put the toilet tank back into place. Replace the bolts and washers with a new set and tighten them carefully. As long as your tank is not cracked, this will correct the leak.
Table of Contents
Why Does Your Toilet Leak Between the Tank and the Bowl?
The most common cause of leaky toilet tanks are bolts that are too loose. Although this can sometimes be corrected by careful tightening, loose bolts are usually caused when the rubber or metal washers on the bolts are old or corroded. Rubber breaks down over time, so an old rubber washer can cause leaks. It can also cause your toilet tank to wobble.
- Loose toilet tank bolts.
- Old toilet washers that no longer provide a watertight seal.
- The gasket connecting the tank and bowl is old and leaky.
- Your toilet tank is cracked.
Another reason your toilet tank is leaking may be the rubber gasket that connects the toilet tank to the bowl. If this gasket is old, compressed, hardened, or damaged, it can allow water to leak out of the tank. Finally, if the bolts in your toilet tank were overtightened at some point, your toilet’s tank may be cracked. A cracked toilet tank is prone to leaks.
10 Steps to Stop Your Toilet Tank Bolts From Leaking
If your toilet tank is leaking from the bolts, it may seem like a costly problem to fix. However, this is a task any DIYer can tackle. Just follow our simple steps to completely eliminate toilet leaks.
Turn Off Water to the Toilet
Locate the water line running from the floor to your toilet tank. There should be an oval-shaped handle on this line. Turn it to the right (clockwise) to tighten it fully. This will shut off the flow of water to your toilet, which allows you to safely empty and remove the tank. You don’t need a wrench for this step. You can simply turn the valve handle by hand to shut off the water supply.
Flush the Toilet
Even with the water flow to your toilet closed, there will still be stored water in the toilet tank. Remove the toilet tank lid to get a good look, then flush the toilet until the tank is empty. This may take 2–3 flushes. With the water line closed, your tank will not refill. Now, you’ll be able to locate and access the tank bolts easily.
Disconnect the Water Line
Before proceeding, find the place where the water line connects to the underside of the toilet tank. It is typically held in place with a plastic nut. Turn this left (counterclockwise) to loosen and remove it. Make sure to do this step after you flush the toilet. Otherwise, water will pour from the tank onto your floor when you disconnect the water line.
Remove the Tank Bolts
Check inside the toilet tank as well as the underside of the tank to locate the bolts holding your toilet tank to the bowl. Some toilet models have 2 bolts, while others have 3 tank bolts. Once you’ve found all the bolts, use an adjustable wrench to remove the nuts. If your toilet tank bolts are stubborn, if the bolt heads spin instead of loosening, or if the bolts are rusted, follow our guide to removing rusted toilet tank bolts.
Lift the Toilet Tank Off the Bowl
Once the old tank bolts have been removed, carefully lift the toilet tank straight up off the bowl. Then, lay the tank down on a towel or bath mat on the floor. It’s a good idea to lay the tank on its side or upside-down so you can easily complete the next few steps.
Inspect the Tank for Cracks
Now that your tank is completely separate from the rest of the toilet, take a closer look. Inspect both the interior and exterior of the tank for cracks in the porcelain. It’s a good idea to use a flashlight to take a good look. Typically, you will see cracks near the bolt holes. This happens when a tank bolt has been overtightened. A cracked tank is prone to leaking and cannot be repaired—it must be replaced. As long as your tank is crack-free, you can move on to the next step.
Replace the Tank Gasket
Begin your leak-prevention toilet maintenance by replacing the rubber gasket on the underside of the tank with the gasket from this universal kit. Remove the old gasket and discard it. If the rubber was old, broken, or hard, it may be the cause of your leak. A new gasket will contribute to a stronger seal and prevent tank leaks. Press the new gasket firmly into place, making sure it fits snugly.
Put the Toilet Tank Back Into Place
Once you’ve installed your new toilet tank gasket, carefully lift your toilet tank and put it back into place on top of the toilet bowl. When taking a toilet tank off or putting it back on, it’s a good idea to enlist a helper for the job. They can help lift, balance, and guide the tank. Once the tank is in place, align the bolt holes in the tank with the corresponding holes in the toilet bowl.
Install New Tank Bolts
Now, you’re ready to replace your toilet tank bolts with a new set, including new washers. It’s always best to use brass bolts instead of stainless steel. Brass won’t rush, but steel will. Additionally, use a set of tank bolts that features high-quality rubber washers. We recommend this set of brass toilet tank bolts. Slot the bolts into place and follow our detailed guide to correctly tighten toilet tank bolts without damaging your toilet.
Turn the Water Supply Back On
With your new tank gasket and bolts installed, simply reattach the water line to the underside of the toilet tank. Then, turn the water line valve to the left (counterclockwise) to resume the flow of water to the tank. Let the tank fill, perform a few test flushes, and watch for any leaks for the next 24 hours. If any leaks do occur, gently tighten the tank bolts a quarter turn at a time until the leaking stops.
Will Tightening Toilet Bolts Stop a Leak?
In some cases, simply tightening loose toilet bolts will stop a leak. However, this is risky if the bolts or washers are old. A hardened or corroded rubber washer can be the cause of a leaky toilet tank. Tightening bolts in this condition can overtighten them without solving the leak. This overtightening puts you at risk of cracking your toilet tank. So, if the toilet tank bolts are more than 3 years old, it’s best to replace them rather than risk cracking the tank by simply tightening the bolts.
How Do You Keep Your Toilet Tank Bolts From Rusting?
The best way to prevent rusted toilet tank bolts is to use brass bolts. Unlike steel bolts, brass will not rust. It is always best to use brass bolts and fittings whenever you are replacing any toilet bolts. This rule applies to tank bolts, as well as seat bolts and flange bolts. Investing in brass will save you from headaches and rusty hardware down the line.
How Do You Stop a Toilet Leaking From the Tank Bolts?
In order to fix a toilet that is leaking water from the tank bolts, you should replace the bolts, washers, and toilet tank gasket. To do this:
- Turn off the water supply to the toilet.
- Flush the toilet tank to empty it.
- Disconnect the water line running to the toilet tank.
- Remove the toilet tank bolts.
- Lift the toilet tank free of the bowl and set it down on a towel.
- Inspect the tank for cracks—if it’s cracked, it must be replaced with a new tank.
- Remove the old tank gasket and replace it with a new one.
- Put the toilet tank back into place on the bowl.
- Replace the old tank bolts with new brass bolts and high-quality rubber washers.
- Carefully tighten the tank bolts.
- Reconnect the water line to the toilet and resume the flow of water to fill the tank.
By following these steps you will eliminate a leaky toilet tank. It’s much safer to remove and replace old bolts than it is to try to tighten old bolts with worn-out washers.
