How to Install a Toilet: Step-by-Step Guide
Installing a new toilet can be a satisfying DIY project if you’re ready to roll up your sleeves. Whether you're replacing an outdated fixture or mounting a new one after a remodel, you need to know how to install a toilet correctly. Here’s what you need to know about installing a toilet before you get started.
Tools and Materials Needed for Installing a Toilet
The toilet facts don’t lie — all toilets will need to be replaced eventually. Whether you’re removing a commercial toilet or a residential toilet, you’ll need some supplies. Here's a list of basic tools you’ll want to have on hand for connecting a toilet:
- Adjustable wrench
- Screwdriver
- Plumber’s putty or silicone caulk
- Wax ring (or a wax-free seal)
- Closet bolts
- Toilet flange (replace if cracked or corroded)
- Level
- Towels or sponge
- Bucket or small container
How to Install a Toilet by Yourself (Step-by-Step)
If you’re ready to learn how to install a new toilet, we’ve got you covered.
1. Remove the Old Toilet
First things first, you’ll have to learn how to remove the old toilet.
- Turn off the water supply by turning the shutoff valve on the wall or on the floor near the toilet.
- Give the toilet one final flush to drain the water from the tank and bowl.
- Disconnect the supply line by unscrewing it with a wrench. A small amount of water will drip out once you remove the supply line, so have a bucket on hand to catch the water.
- Take the tank top off. Simply use an adjustable wrench to remove the bolts at the bottom of the tank. Lift straight up and twist.
- Remove the toilet by loosening the bolt caps on the base of the appliance. With a partner, rock the bowl back and forth to free it from its wax gasket.
2. Inspect and Prep the Flange
- Remove the gunk where the old toilet sat with a putty knife to scrape the wax off the base.
- Clean and level the mounting surface before you proceed with the installation of the new toilet.
- Check the toilet flange for damage. If it's broken or rusted, you’ll want to replace it.
- Remove the old flange bolts. Just slide them around to the opening so they’ll come out of the flange.
- Place the new flange bolts into position on the toilet flange.
3. Position the New Wax Ring
- Place a new wax ring or wax-free gasket onto the bottom of the toilet bowl outlet (also called the horn).
- Center it carefully — this creates your water-tight seal. It’s also relatively air-tight and will prevent sewer gases from coming through.
4. Position and Mount the Toilet
- Flip the toilet over and place it onto the base.
- Gently press down against the wax ring.
- Rock the bowl back and forth a couple of times to make sure it's secure.
- Tighten the nuts on the new flange bolts, alternating sides to keep even pressure. Don’t overtighten — porcelain can crack.
- Some models, like dual-flush toilets, may have special instructions from the manufacturer that you need to follow.
5. Attach the Tank
- Slide the tank bolts through the opening at the bottom of the tank.
- Once they're aligned, slowly drop the tank down.
- Secure the tank in place by tightening a nut onto each bolt. Be careful not to overtighten, or you will crack the porcelain.
How to Mount a Toilet Securely
No matter what type of toilet you’re installing, mounting it correctly is one of the most important steps. Here are some additional tips to keep in mind:
- When lining up the toilet with the flange bolts, carefully lower the bowl straight down onto the flange, keeping it level. Don’t tilt or twist — it can ruin the seal.
- Hand-tighten the nuts first, making sure they’re even on both sides before moving to your wrench.
- Check for rocking. If the toilet isn’t sitting level, use plastic toilet shims around the base until it’s stable. Recheck your bolts afterward.
- Add a bead of silicone caulk around the base. This helps anchor the toilet to the floor and prevents spills from seeping underneath. Just be sure to leave a small gap at the back so leaks are visible if they ever occur.
Connecting a Toilet to the Water Supply
Now that you know how to mount a toilet, you have to finish the job by installing the water supply line.
- Attach the water supply line to the fill valve under the tank and tighten it gently with an adjustable wrench. It’s wise to replace the old water supply line with a new flexible, stainless steel braided supply hose.
- Slowly turn on the shut-off valve and allow the tank to fill.
- Check for leaks around the base and supply connection.
Replacing the supply line? Here’s how to change a toilet’s water supply line.
Frequently Asked Questions
How do you install a new toilet?
You’ll need to remove the old unit, check the flange, place a new wax ring, mount the new toilet, and connect the water supply. The process is straightforward but requires careful alignment and sealing.
Can I install a toilet myself?
Yes, many homeowners install their own toilets. However, if the flange is damaged, the floor is uneven, or the water line is outdated, it’s worth calling in a pro.
Do I need to replace the flange when installing a toilet?
Not always. If your flange is intact and level, you can reuse it. But if it’s cracked, rusted, or sits too low or high, you'll need a new one. You’ll also want to replace the flange if you want to move your toilet to a different spot.
How long does it take to install a toilet?
For DIYers, expect about 1 to 2 hours. Experienced pros can often do it in under an hour, depending on site conditions.
How much does it cost to install a toilet?
If you’re doing it yourself, you’ll just need to pay for the costs of the toilet and installation supplies. But how much does a plumber charge to install a toilet? They’ll tack on labor charges for the time they spend performing the installation.
How hard is it to install a toilet without a plumber?
If you're comfortable with basic plumbing tasks, it's doable. The most challenging parts are aligning the toilet properly and ensuring a leak-free seal. For wall-mounted toilets, installation is more complex.
When to Call a Professional for Toilet Installation
If you're dealing with corroded pipes and cracked flanges or don’t want to risk a leak, hiring a licensed plumber is a smart move. They’ll ensure everything is installed to code — and handle any surprises. They can even point out the signs that it’s time to replace your toilet if you’re on the fence about replacement or repairs, or offer advice on an upgrade to a more efficient or luxurious toilet.
Roto-Rooter’s licensed plumbers can install your toilet quickly and correctly the first time. Whether it’s a basic replacement or a complex remodel, our team has the tools and know-how to get it done right. Schedule your appointment now to get started.