How Tight Should Toilet Tank Bolts Be? [7 Tips to Get it Just Right]

Because porcelain toilets are relatively brittle, it’s important to tighten toilet tank bolts carefully. The best way to do so is to hand-tighten the nuts on the tank bolts, then use a wrench to make a quarter-turn on each nut. Once you’ve done this, check to see if the tank wobbles or leaks. If the tank seems loose or is not sealing water inside, gradually tighten the bolts a little at a time. Make sure to tighten all tank bolts equally, to prevent differential stress that could crack your toilet. Once the tank is snug, observe it for 24 hours. If it leaks, gradually tighten the bolts until the leaking stops.

Can Toilet Tank Bolts Be Too Tight?

Overtightened toilet tank bolts will crack the toilet tank or the bowl you are attaching it to. This is because toilets are made of porcelain, which is very hard but is prone to cracking. Porcelain won’t bend or flex, so an overtightened bolt will crack the ceramic. If this happens, you’ll have to purchase a replacement for the cracked part.

• Overtightened toilet tank bolts will crack the toilet bowl or tank.
• Toilets are made from ceramic, which does not flex. If stressed, it will crack.
• Use a small wrench and work slowly.

When tightening toilet tank bolts, the best practice is to work carefully with small tools. If you use a large wrench, you can place too much torque on the toilet bolts without realizing it. Opt for a small socket wrench for this delicate job.

7 Tips for Tightening Toilet Tank Bolts

You can tighten your toilet tank bolts easily using just a screwdriver and an adjustable wrench. Don’t be daunted by reports of individuals cracking toilet tanks when performing a home install. By following the tips below you will complete your project with a functioning, crack-free toilet.

Use Rubber Washers

Most toilet tank bolt kits sold in stores and online include rubber washers, but you may need a few extras. Wherever a metal or plastic washer would be pressed against porcelain when the bolt is tightened, use a rubber washer between the porcelain and the metal washer.

• Use a rubber washer wherever a flat washer would come in contact with porcelain.
• Inside the toilet tank, you should have a rubber washer against the bottom of the toilet tank, with a metal flat washer on top, followed by the bolt head.
• Outside the toilet tank, you should have a rubber washer against the porcelain, followed by a metal washer, and then secured by the nut.

This system necessitates rubber washers both inside the toilet tank and on the underside of the bowl flange, where the tank connects to the bowl. This will protect your toilet tank while tightening. The rubber washers will flex slightly as you tighten, absorbing strain and preventing your toilet from cracking.

Hand-Tighten and Quarter-Turn

Once your washers are in place, thread the nuts onto the toilet tank bolts. Using only your fingers, tighten the nuts. Make sure to do this to all tank bolts before moving on. Some toilet models have two tank bolts, while others have three.

• Thread the nuts onto the tank bolts by hand.
• Finger-tighten the nuts.
• Finger-tighten all tank bolts before moving on.
• Once the nuts are finger-tight, use a wrench to make a quarter turn to each nut.

After you’ve tightened the nuts by hand, use an adjustable wrench or socket wrench to make a quarter turn to tighten each nut. A quarter turn is accomplished by tightening the wrench on the nut and turning it 90 degrees. If it helps, think of your wrench handle as the hour hand of a clock. Turn the wrench handle from 6 to 9 o’clock.

Bolts Don’t Have to Be Extremely Tight

In some cases, hand-tightening and a quarter-turn is all you need. It’s important to keep in mind that the toilet tank is not intended to take weight and strain. The tank-to-bowl bolts are merely there to ensure the rubber seal between the tank and bowl is snug and leakproof.

• Tank bolts do not need to be tightened to an extremely snug position. They are not strain-bearing bolts.
• The purpose of the bolts is to ensure a secure seal between the tank and the toilet bowl.

One of the most common mistakes in toilet installs is thinking that the tighter the bolt, the better it is. Avoid this way of thinking. What you need are bolts that are tight enough to do the job without putting stress on the ceramic toilet base or tank.

Check for Wobble Before Tightening Further

Before you tighten your bolts beyond the hand-tighten and quarter-turn, use your hand to check how secure the tank is to the base. If there is no wobble, you don’t need to tighten any further at this time. If the tank does wobble, you will need to tighten it some more.

• Check the tank to see if there is any wobble.
• If the tank does not wobble after the first tightening, no further tightening is necessary at the moment.
• If the tank does wobble, tighten the bolts in small increments.

When tightening a toilet bolt after the initial quarter turn, work in small increments. Think of moving that wrench handle from 6 to 7 o’clock, gradually tightening.

Tighten Bolts Equally

When tightening toilet tank bolts, it is essential to work in small increments and tighten each bolt equally. After tightening one bolt slightly, move to the other bolts and tighten them to the same degree. Tightening each bolt a little at a time may be time-consuming, but it results in a level toilet tank that won’t wobble.

• Move from bolt to bolt, tightening each in equally small increments.
• Overtightening one bolt leads to cracks in your toilet or a poor seal between the tank and bowl.

Always tighten bolts equally in small increments. Overtightening one bolt increases the chance of cracking your toilet or creating a leaky seal between the tank and bowl.

Inspect the Rubber Washers

Keep an eye on the rubber washers both inside and outside of the toilet tank as you tighten the bolts. Once the rubber washers on either side begin to flatten, squash, or deform, it’s time to stop tightening. Continuing to torque the bolts past this point will crack your toilet.

• Check the rubber washers on the inside and outside of the tank as you tighten.
• Once the rubber washers change shape from the pressure of the tightened bolts, it’s time to stop tightening.
• Tightening bolts when the rubber washers have already been deformed will damage your toilet.

In many cases, you can achieve a tight seal between the toilet tank and bowl without tightening so much that the rubber washers deform. If the washers have begun to squash under the pressure of the bolts, it’s a warning sign that you’ve tightened the bolts to the limit of their safety.

Observe for Leaks

Once you’ve tightened the bolts equally to achieve a firm, wobble-free seal, your work is usually done. However, it’s good practice to watch for leaks between the toilet tank and the bowl over the next 24 hours. If water is pooling on the bathroom floor around the toilet at this time, it is typically a sign of a leaking toilet.

• After securing the tank to the bowl, keep an eye out for water leaking onto the ground from a bad seal.
• Verify that any leaks are coming from the tank before tightening the tank bolts. In a new toilet install the leak may be coming from between the toilet flange and the floor.
• If the leak is coming from the tank, follow the previous steps to gradually tighten the bolts safely.

If your toilet is leaking, carefully tighten the bolts that hold the tank to the bowl. Then, clean up any leaking water and observe for the next 24 hours. Once the toilet stops leaking, your job is complete. For additional coverage, we recommend using Vivint’s water sensors as part of their home security system to instantly be notified of any leaking, without you needing to be there.

How Much Should You Tighten Toilet Tank Bolts?

It’s essential to make sure you don’t overtighten bolts when securing a toilet tank to the bowl, to secure your toilet tank safely, do the following:

• Use rubber washers inside the toilet tank and on the outside—between the toilet and any metal washers.
• Hand tighten the nuts on the tank bolts. Then, use a wrench to make a quarter-turn to tighten each nut.
• Remember, the purpose of the tank bolts are to create a good seal between the tank and the bowl. They do not need to be extremely tight.
• After performing the initial tightening, check to see if the tank wobbles before tightening any further.
• Tighten bolts in small increments. Tighten all bolts equally to prevent cracking your toilet.
• Check the rubber washers on the inside and outside of the tank. Once they begin to squash or deform, do not tighten any further.
• Use your toilet as normal for 12–24 hours. If the tank leaks onto the ground, the bolts require additional tightening. If there are no leaks, your work is done.

These tips will reward you with a secure, leak-free toilet tank every time. Not only that, but they protect your toilet from cracks and damage.