DIY Toilet Installation: A Complete How-To Guide

Installing a new toilet is a lot easier than you may think. In fact, many homeowners choose to remove their old toilet and replace it with a new one without the help of a handyman or plumber. If you do decide to make installing a toilet your new DIY project, you should know the basics. We talked to professional plumber Dave Jones to find out how to remove your old toilet and replace it with a brand-new one to give your bathroom a breath of fresh air.

Quick Guide to Installing a New Toilet

Remove the old toilet.
Replace the bolts and wax ring on the flange.
Carefully lower the new toilet into place and tighten the bolts.
Attach the tank to the back of the toilet.
Connect the water supply line and fill the toilet.

Section 1 of 4:

Removing the Old Toilet

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1
Measure the distance from the wall to the toilet floor bolts. It's a good idea to check the size of your toilet before you remove it, so you know the new one will fit. Place the end of a measuring tape against the wall behind the toilet and extend it until it reaches the center of the toilet's floor bolts. This distance is called the “rough-in.”^{[1]
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- Toilets commonly come in three sizes, based on their rough-in: 10 in (25 cm), 12 in (30 cm), and 14 in (36 cm). Toilets with a 12 in (30 cm) rough-in are the most common.
- Take your measurements to the hardware store to look for a toilet that will fit your space.
2
Turn off the water at the supply valve. According to Jones, "This is usually accomplished by turning a valve to the right. If it's an older-style gate valve, it will require several turns before it closes. If it's a quarter-turn valve, you only have to turn the valve one-quarter of a 360-degree turn."^{[2]
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Expert Source

Dave Jones
Master Plumber, Roto-Rooter Plumbing & Water Cleanup

Expert Interview. 13 December 2021.}
- Turning off the supply valve cuts the water to the toilet, so you can replace it with less mess.
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3
Set the lid aside and flush the toilet to drain the basin and the bowl. Jones recommends putting the lid in a safe spot where it won't get broken or tripped over. Then, flush the toilet a few times until you've removed as much water from the tank as possible.^{[3]
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Expert Source

Dave Jones
Master Plumber, Roto-Rooter Plumbing & Water Cleanup

Expert Interview. 13 December 2021.}
- You won't be able to flush all of the water out of the tank, but we'll walk you through what to do.
4
Put on gloves and remove the rest of the water. Jones recommends wearing thick, heavy-duty gloves to protect yourself from bacteria. Then, he says to get out a large sponge and press it into the tank, so it absorbs the remaining water. Squeeze it out into a bowl and repeat the process for the toilet bowl.^{[4]
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Expert Source

Dave Jones
Master Plumber, Roto-Rooter Plumbing & Water Cleanup

Expert Interview. 13 December 2021.}>
- If you've got quite a bit of water left in the bowl or tank, you can use a cup to scoop it out before you switch to a sponge.
- Discard the water and thoroughly wash the bowl out.
5
Remove the water supply line from the wall and tank. Use an adjustable wrench to unscrew the nut at the back of the toilet. Then, unscrew the water supply line nut near the stop valve that you turned to switch off the water. Pull away the water supply line and discard it.^{[5]
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- Most plumbers recommend replacing your braided water supply line every 3 to 5 years.
6
Unscrew the tank bolts that fasten the basin to the bowl. If the bolts aren't visible, pop off the bolt covers. Then, Jones says to use a wrench to loosen the nuts that are securing the toilet to the floor. Discard the nuts and washers.^{[6]
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Expert Source

Dave Jones
Master Plumber, Roto-Rooter Plumbing & Water Cleanup

Expert Interview. 13 December 2021.}
- Sometimes, nuts and washers can become so rusty that you can simply remove them by hand.
- If you see caulking along the base of the toilet, carefully run a utility knife along it, so you can pull the toilet up.
7
Lift the toilet up and away from the floor. Although you may be able to lift the entire toilet by yourself, it can help to have another person lift one side of the toilet. According to Jones, the safest way to remove the toilet is to lift with your legs and keep your back straight.^{[7]
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Expert Source

Dave Jones
Master Plumber, Roto-Rooter Plumbing & Water Cleanup

Expert Interview. 13 December 2021.}
- Once you pull the toilet up from the floor, remove it from your bathroom.
- If you're setting the toilet down in your home instead of outside or in a garage, place it on an old towel or tarp until you can throw it away.
- If you're working by yourself and want to make the toilet lighter before you remove it, unscrew the bolts from the inside of the tank. Then, lift the tank away so you're only pulling up the toilet base.
8
Pry away the wax seal from the toilet flange. The flange is the circular opening and you'll see brown wax covering it. Take a putty knife to scrape away the waxy residue and debris. Leave the metal or plastic flange in place.^{[8]
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- If there's still a lot of sticky wax on the flange, wipe it off using a damp cloth.
- If the flange is cracked or damaged, replace it before you continue installing the toilet.
9
Plug the drain opening with an old rag or cloth. Stuffing the drain hole in the floor will prevent sewage fumes from wafting into your bathroom before you install the new toilet. It will also block tools from accidentally falling into the hole.^{[9]
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- Be sure to remove the rag before you install the new toilet.

Section 2 of 4:

Installing the New Toilet

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1
Replace the toilet bolts on the flange. Jones says that new toilets usually include a new set of toilet bolts, so unscrew the old nuts with a wrench and pull out the bolts. To insert the new bolts, put the bolt head facing down into the large opening on the flange. Then, slide the bolt to the narrow end of the slot and repeat this for the opposite side.^{[10]
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Expert Source

Dave Jones
Master Plumber, Roto-Rooter Plumbing & Water Cleanup

Expert Interview. 13 December 2021.}
- Toilet bolts are also called closet bolts.
2
Fit a new wax ring around the flange. Most new toilets come with a wax ring, but it's always a good idea to check. Open the new wax ring and center it on the flange. If your wax ring has a sloped edge, place it upside down so the narrow end of the wax ring touches the flange.^{[11]
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- Wax rings can last 20 to 30 years if they’re well-maintained. If your toilet starts leaking near the base, you'll know it's time to replace the wax ring.
3
Center the toilet base over the toilet bolts on the floor. Jones says, “Carefully pick up the new toilet base and set it down directly over the flange so the bolts extend through the bottom sides of the toilet. Then, press down and rock the toilet back and forth so it seals to the wax ring.”^{[12]
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Expert Source

Dave Jones
Master Plumber, Roto-Rooter Plumbing & Water Cleanup

Expert Interview. 13 December 2021.}
- It can help to have another person lifting the toilet or guiding it onto the bolts.
- Once you've pressed the toilet to the wax ring, don't remove the toilet again or you'll break the seal.
4
Tighten the toilet bolts on the base. Set a plastic washer onto each bolt and screw a nut onto the bolts by hand. Then, use a wrench to finish tightening the bolts, but go back and forth between the two bolts. Stop tightening as soon as the nut is snug. This way, you're applying even pressure on the toilet so it stays level and the bowl doesn't crack.^{[13]
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- The toilet bolts will stick way up even after you've installed the washers and nuts. This is completely fine, since you'll saw them down.
5
Cut the excess length from the bolts and pop on decorative caps. According to Jones, it’s normal for the new bolts to be too long. He says, “Use a hacksaw to cut off away the excess length of the bolts—leave about ¹⁄₂ inch (1.3 cm) of bolt above the nut. Then, push the decorative caps over each bolt, so they're no longer visible.”^{[14]
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Expert Source

Dave Jones
Master Plumber, Roto-Rooter Plumbing & Water Cleanup

Expert Interview. 13 December 2021.}
- Brush away the metal filings with a clean cloth or suck them up with a vacuum.
- Many new toilets will come with the seat already installed. If yours came separately, attach it now using the included bolts.
6
Place the gasket on the tank and push the tank bolts through the holes. Turn the new tank on its side and push the rubber gasket onto the bottom opening of the tank. Then, slide the tank bolts through the inside of the tank so they extend out of the tank's bottom.^{[15]
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- Sometimes, tanks come pre-assembled, so you may not need to do this step.
7
Set the tank onto the toilet bowl and screw it in place. Turn the tank right side up and fit it over the bowl, so the bolts slide right into the holes on the back of the toilet bowl. Then, screw the bolts by hand before you use a wrench.^{[16]
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- Alternate tightening the screws so you apply even pressure.
8
Install a new water supply line and connect it to the toilet tank. Screw one end of a new supply line onto the bottom of the toilet tank. Then, screw the opposite end onto the supply valve near the wall. Tighten both ends with a wrench until the connections are snug.^{[17]
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- You can buy braided water supply lines from hardware stores or online. They sell a variety of lengths, so you're sure to find one that will fit your toilet.
9
Turn on the water supply valve and flush the toilet. Jones says to open most valves, turn them to the left. For an older-style gate valve, keep turning until the valve opens. You should see water filling the toilet tank. Wait until it's full and flush the toilet.^{[18]
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Expert Source

Dave Jones
Master Plumber, Roto-Rooter Plumbing & Water Cleanup

Expert Interview. 13 December 2021.}
- Check around the toilet base and near the water supply line for leaks. You may have to tighten the bolts if you see them leaking.
10
Caulk around the bottom of the toilet. Insert a tube of silicone tub and tile caulk into a caulk gun. Run the caulk all the way around the base of the toilet, so there's no gap between the toilet and the floor. Then, drag your fingertip through the caulk to smooth the line and remove excess product.^{[19]
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- Most caulking products require about a day to cure, so avoid mopping the floor around the toilet. Use 100% silicone caulk or one designed for kitchen and bath for a faster cure time and mildewcide properties.

Section 3 of 4:

When to Call a Professional

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Call a plumber if you’re unsure about the process. Installing a toilet is fairly easy, but it does require lifting the toilet into place and lining it up just right with the bolts. This step is best done with two people—one to lift the toilet and the other to help guide the base onto the bolts. If you don’t have anyone who can help you lift the toilet, have a professional come in and install it for you.
- You should also call a plumber if you’ve tried to install the toilet but it’s leaking, or if you think there’s an issue with the plumbing under the toilet.

Section 4 of 4:

FAQs

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1
How much does it cost to install a toilet? On average, it costs somewhere between $350 and $800 for a professional to install a toilet. This includes the cost of parts and labor.^{[20]
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- If you need a toilet in a custom size or you choose a high-end toilet (like a smart toilet or a high-tank toilet), you may pay more.
2
Why should you caulk around the base of a toilet? Caulking around the base of a toilet can make it more stable, and it will also look nicer. Also, in some places, you may be required by code to caulk around the toilet.^{[21]
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3
How do you deal with uneven floors when replacing a toilet? If the floor under the toilet is uneven, place plastic shims under the toilet to help keep it level. You can also apply epoxy mortar to the floor around the toilet flange before you install the toilet.^{[22]
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- Do not use wood shims to level a toilet—they’ll rot quickly in a humid bathroom environment.
4
How do you maintain a newly-installed toilet? Toilets are fairly low-maintenance when they’re running well. Clean it regularly, and inspect around it for leaks. If you notice any wear to the toilet parts like the flapper valve, chain, handle, and bolts, replace them right away.^{[23]
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5
How often should you replace toilet parts? The rubber on a toilet flapper valves break down over time, so they need to replaced every few years. Most of the other parts of a toilet, including the handle, fill valve, and chain, will only need to be replaced if they become worn or damaged.^{[24]
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Question

What is the first step when installing a toilet?

Dave Jones
Master Plumber, Roto-Rooter Plumbing & Water Cleanup
Dave Jones is a Professional Plumber and the Midwest Regional Vice President at Roto-Rooter Plumbing & Water Cleanup. In 1992, Jones joined Roto-Rooter as a drain service technician at the age of 18. Since then, he has risen through the ranks into positions of increasing authority. Dave served as general manager of Roto-Rooter’s Charlotte, North Carolina, and Atlanta, Georgia branches before being promoted to Contractor Area Manager and later to Regional Vice President. Dave holds Master Plumber Licenses in Pennsylvania, North Carolina, and Georgia.

Dave Jones

Master Plumber, Roto-Rooter Plumbing & Water Cleanup

Expert Answer

Be sure you have toilet flange bolts and a new wax ring for sealing your toilet to the bathroom floor. These normally come in the box when you purchase a new toilet. Also, if you didn’t get any toilet flange bolts with your new toilet, go to a hardware store or home center and purchase a pair of those.

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Question

Where should I put the old toilet?

Dave Jones
Master Plumber, Roto-Rooter Plumbing & Water Cleanup
Dave Jones is a Professional Plumber and the Midwest Regional Vice President at Roto-Rooter Plumbing & Water Cleanup. In 1992, Jones joined Roto-Rooter as a drain service technician at the age of 18. Since then, he has risen through the ranks into positions of increasing authority. Dave served as general manager of Roto-Rooter’s Charlotte, North Carolina, and Atlanta, Georgia branches before being promoted to Contractor Area Manager and later to Regional Vice President. Dave holds Master Plumber Licenses in Pennsylvania, North Carolina, and Georgia.

Dave Jones

Master Plumber, Roto-Rooter Plumbing & Water Cleanup

Expert Answer

Sit the toilet on a towel or old blanket to prevent damage to your floor until you’re able to remove the toilet from the bathroom.

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Is it necessary to caulk around the base of the toilet?

Community Answer

If you caulk around the base, you will not know if it is leaking. It's a nice touch, but not good to do. If the toilet sits level and looks good to the floor, then don't caulk it. I have installed many toilets. If it does not leak, let it go.

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You can install an antique or vintage toilet as long as the measurements work for your space.

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Use solid brass closet bolts instead of brass plated. They will not rust and so it will be easier to remove the toilet in the future when necessary.

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