• By Champion Inspect

How to Properly Install a Toilet

Updated: Jun 27, 2019

Whether you're installing a better-flushing toilet or resetting the old one after remodeling, these tips will help you do it faster and with fewer problems.

Measure Before Buying

If you’re buying a new toilet, you need to know the “rough-in” measurement of the old one. For the vast majority of toilets, the waste pipe is centered about 12 in. from the wall. But with a few models, that measurement is 10 in. or 14 in. To check the rough-in, just measure from the wall to the toilet’s hold-down bolts. If that measurement (plus the thickness of the baseboard) isn’t approximately 12 in., toilet shopping will be a bit harder. Most home centers carry only one or two 10-in. models and no 14-in. models. If you have to special-order a toilet, be prepared to spend little more. If there’s a door near the toilet, also measure how far the bowl protrudes from the wall. If you are replacing a toilet with a standard bowl with an “elongated” model, the door may not close. Read on to learn how to install a toilet.

Remove the Old Toilet

Once you have your new toilet, you can start removing the old one. Since toilets are heavy, it’s easier to remove the tank first, then the bowl.

#1 - Turn off the water supply line and flush the water from the tank. Remove the rest of the water in the tank with a sponge

#2 - Disconnect the water supply lines from the tank. Position a bucket to catch any water remaining in the bowl or lines. Unscrew the nuts on the bottom of the tank and lift it off the bowl. Wear gloves in case it cracks.

#3 - Use a water solidifier to keep any remaining water from sloshing out of the bowl. This helps eliminate spills during toilet removal with a Gel that solidifies water in approximately 4 minutes to help prevent drips and leaks during toilet replacement. You could also use a sponge to get the water out.

Loosen and remove the nuts holding the toilet bowl to the floor. Lift the bowl and set it out of the way on a garbage bag.

#4 - Remove the old wax ring. Wax rings cannot be reused.

#5 - Stuff a rag in the hole to block sewer gases and prevent anything from falling into the drain. Use a putty knife to remove any excess wax on the flange (the top of the drain pipe).

Champ Tip: If you don’t like the thought of your putty knife being used on a sewer drain, use a plastic putty knife or shim to remove the old wax ring. They’re budget-friendly and can be thrown away after you’re finished with the job.

#6 - Remove the old closet bolts from the flange.

#7 - Make any repairs to the flange as needed. Repair kits are available to fix a broken flange. Replacement flanges are also available to fit inside the pipe and create a tight seal.

The flange should be a little higher than your finished floor. However, if you’re adding new flooring your flange could be too low. Products are available to create the proper seal when the toilet is in place, such as taller wax rings and flange spacers.

Taller wax rings install just the same as a typical wax ring. Some are wax-free and use foam and rubber to create a seal.

Flange spacers sit on top of the existing flange. You must use silicone between the spacer and flange to create a seal, then secure the spacer to the subfloor.

Install the New Toilet

Once you've ensured the flange is in good shape, you can install the new toilet.

#1 - Install new closet bolts by sliding them in the slots on the flange. Some have washer/nuts to hold them in place on the flange. Tighten down these washers so it’s easier to align your toilet when setting in place.

Champ Tips: If your old toilet was rocking while in place, you can help stabilize it with toilet shims. To install them, set the toilet in place without the wax ring. Use the shims to stabilize the toilet and tape in place. Remove the bowl and continue the installation with the wax ring. After the toilet is installed, cut the excess shims with a knife.

#2 - Set the new toilet bowl upside-down on a towel. Run the wax ring under warm water to soften it, and gently press the ring onto the toilet outlet.

Champ Tips: Toilets usually include a wax ring. However, it’s best to purchase a backup wax ring in case of damage during installation.

You can also use a wax-free ring. These types of rings install on the flange, rather than the toilet outlet. They are easier to install than a typical wax ring, and there is less potential for damage during installation.

#3 - After your wax ring is set, remove the rag from the drain. Carefully lower the toilet bowl over the new closet bolts. Try to lower it straight down over the flange rather than tilting and rocking into place. This will help prevent damage to the wax ring.

Firmly press down on the bowl and make sure it’s square with the wall.

#4 - To secure the toilet, add the cap bases, washers and nuts to the closet bolts. Make sure the cap bases have the correct side facing up.

Alternate tightening the nuts to keep the pressure even. Make sure the nuts are firm, but don’t tighten too much. The bowl could crack. Then use a hacksaw to cut off the excess bolt. Snap on the caps.

#5 - Prep the tank for installation. Typically, the valve assembly is already installed in the tank. Flip over the tank to install the bolts that will hold it to the bowl. They should slip into slots on the tank. Then install the rubber gasket to the base.

#6 - Set the tank in place on the bowl. Hand tighten the nuts on the bolts. Then use a wrench to make them a little bit tighter, alternating as you go. Be careful not to over tighten the nuts and crack the toilet. Make sure the tank is level.

#7 - Hook up the water supply and slowly turn on the water.

#8 - Check for leaks around the supply line and the gasket base. If it is leaking, tighten the bolts a little more. If it continues to leak, take the tank back off and be sure the gasket is seated correctly. Flush the toilet a few times and check around the base. If you have a leak around the base and the nuts are tight on the closet bolts, the wax ring isn’t creating a tight seal. You’ll need to remove the toilet and install a new wax ring. Be sure to evenly set the toilet in place – not tilt – to avoid damaging the ring.

#9 - Install the seat with a screwdriver and set the top on the tank.

Required Tools for this how to install toilet Project

Have the necessary tools for this DIY how to install a toilet project lined up before you start - you’ll save time and frustration.

4-in-1 screwdriver

Adjustable wrench

Caulk gun

Cordless drill



Locking pliers



Shop vacuum

Slip joint pliers

Tape measure

Utility knife

Required Materials for this how to change a toilet Project

Avoid last-minute shopping trips by having all your materials ready ahead of time. Here’s a list.

Brass toilet bolts


Flexible water supply

Plastic shims

Toilet flange

Wax ring

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