How to Repair a Toilet Leaking From Tank Bolts in 5 Easy Steps

If you see water pooling on the floor next to the toilet, you’ll want to check all toilet areas to find the source of the leak.

Start at the bottom of the toilet and feel your way up. Check if the toilet tank is wobbling—if so, you may only need to tighten the tank bolts with an adjustable wrench to fix the leak.

If tightening the bolts does not stop the leak, you’ll need to check whether the bolts, washers, and nuts are rusted or damaged. You may need to replace these parts entirely. Universal tank bolt kits are easy to find and purchase—averaging $5 per kit.

If you’re unsure where your toilet leak is coming from, you can reach out to a plumbing repair expert in your area to save you time, money, and hassle.

Locate the water supply valve—usually found behind the left side of the toilet.

• Place a small bucket underneath the valve to catch excess water.

• Grab your adjustable wrench, loosen the nut on the valve and slowly turn clockwise until you shut the valve off.

• Flush the toilet to empty any water from the toilet bowl.

• Take off the tank lid and place it in a safe spot where it won’t break.

• Remove water remaining inside the toilet tank with a sponge. Wring out the water in your bucket.

Check the condition of the nuts, bolts, and washers. If they’re metal, they may be rusty and difficult to disconnect with a wrench—you may need to saw them off with a mini hacksaw. Otherwise, grab a wrench, pliers, or a screwdriver. Loosen the nuts, then turn bolts to the left until they disconnect.

Remove all bolts, nuts, and washers from the tank and the bowl. Lift the tank up—lay a towel on the ground, and place it on its side. While everything is removed and visible, take a moment to check for mold or mildew that may be a result of the water leak.

Take all loose parts and place them in a separate area from your new replacement kit parts. When changing your nuts, bolts, and washers, you’ll also want to replace the bowl gasket—the round rubber piece that sits between the toilet bowl and the tank to prevent leaks in the future. Place the new gasket on the bottom of the tank, open your kit and make sure you have the correct replacement parts.

Pro Tip: You may want to purchase additional washers—metal and rubber—to add an extra layer of security to your tank bolts.

You may need another person or a professional plumber to hold the toilet tank in the correct position for this step.

• Align tank bolts with connecting holes.

• Place a metal washer followed by a rubber washer on the bolt.

• Slide the tank bolt into the hole and add another washer to the bolt under the tank.

• Put a nut on each bolt underneath the tank. Tighten the nuts with your hand—and then gently use a tool tightener. 

• Carefully lift the tank and place it over the holes on the bowl. 

• Add a third rubber washer—and an additional metal washer on the tank bolt, followed by a nut under the bowl. Gently tighten.

• Double-check to ensure you didn’t miss installing the tank bolts, nuts, and washers inside and below the tank—and under the bowl.

• Grab your water supply line. Hand turn the nut counter-clockwise, turn the water back on, and let the tank fill up. 

• Flush the toilet a few times—feel around the tank, bowl, water valve, and tank bolts for any leaks.

Pro Tip: If you secure the fasteners too tight, it can cause the porcelain to crack.