Install a Toilet: Step-by-Step Guide for Beginners

Installing a toilet was one of our first DIY projects after buying a house in 2006. Nearly two decades later we’ve installed and reinstalled toilets so many times the process feels routine. You’ll see photos from several bathrooms throughout this guide. While installing a toilet can seem daunting or unpleasant, it’s a straightforward project most homeowners can tackle with a few basic tools and some patience.

This walkthrough works for replacing a toilet, fixing a leaking or rocking toilet, or reinstalling an existing unit during a bathroom remodel.

Tools & Supplies Needed

You don’t need many specialty tools. Here are the most useful items to have on hand:

• New toilet (optional if reusing the existing one)
• Measuring tape
• Wax ring kit (consider a standard and an extra-thick option)
• Adjustable wrench or groove-joint pliers
• Flathead screwdriver
• Spare rags and towels or blankets
• Sponge, paper towels, or a small bowl for water removal
• Utility knife
• Hacksaw
• White silicone caulk
• Level (optional)
• Gloves (optional)

If you’re reinstalling the same toilet, a new model isn’t required. Steps below cover reusing an existing toilet.

Steps To Install A Toilet

Read this entire guide before starting and gather your supplies. Below is a quick overview of the steps you’ll follow.

1. Measure your rough-in
2. Purchase a toilet (if needed)
3. Remove the old toilet
4. Prepare the floor and flange
5. Add the wax ring
6. Place the toilet bowl
7. Bolt the bowl to the floor
8. Install the tank
9. Connect the water line
10. Finish the installation

Some steps may be optional if you are reusing the same toilet.

Step 1: Measure Your Rough-In

Before buying a toilet, measure the rough-in: the distance from the floor bolts to the finished wall. Most toilets use a 12″ rough-in. Older or compact bathrooms may require a 10″ model. Use a tape measure and remember to account for baseboard depth, since tank dimensions typically sit above the baseboard.

Step 2: Purchase Your New Toilet

When choosing a toilet, consider these common options:

• Round vs. Elongated: Elongated bowls are often more comfortable while round bowls save space.
• Standard vs. Comfort Height: Standard height is about 14–15″ to the seat; comfort or chair height is closer to 17″.
• One- vs. Two-Piece: Two-piece toilets are lighter to handle during installation; one-piece models offer a seamless look.
• Single- vs. Dual-Flush: Dual-flush options save water by offering different flush volumes for liquids and solids.

Other features include color, flush performance, and unique mounting styles. Choose a model that fits your rough-in and personal preferences.

Step 3: Remove Your Old Toilet

Removing an existing toilet reverses the installation steps. The basic sequence:

• Turn off and empty the water
• Disconnect the water supply line
• Unscrew and remove the tank
• Unscrew and remove the bowl
• Plug the flange opening with a rag

Turn off & empty water

Shut the shut-off valve behind the toilet by turning it clockwise. Flush to drain the tank and bowl, and use a sponge or small bowl to remove remaining water.

Disconnect the water line

Disconnect the supply line at the tank by turning the nut counterclockwise. Have a towel or bowl ready for spilled water. You can leave the supply line attached at the wall unless you plan to replace it.

Unscrew & remove the tank

For two-piece toilets, remove the tank first by unfastening the nuts beneath the tank bolts. You may hold the bolt steady with a screwdriver inside the tank while loosening the nut. Set the tank on a towel to protect it from the floor.

Unscrew & remove the bowl

Remove the nuts from the floor bolts (often under plastic caps). Score any caulk around the base with a utility knife. Rock the bowl gently to break the wax seal and lift it free. Place the bowl on a towel or blanket, upside down or on its side to avoid getting wax on the floor.

Plug the flange hole

Immediately stuff a rag into the open flange to block sewer gases and prevent debris from falling in. Remove it before installing the new toilet.

Step 4: Prepare The Floor & Flange

Clean old wax, caulk, and debris from the flange and the surrounding floor. Use a utility knife, putty knife, or flathead screwdriver to scrape away residue. If the flange is damaged, replace it; otherwise clean it for reuse.

Remove old floor bolts and install the new bolts from your wax ring kit. Many kits include plastic clips to help keep bolts upright. If you’re reusing a bowl, clean any old wax from its underside as well.

Step 5: Add The Wax Ring

The wax ring seals the toilet to the flange. Many kits include multiple rings; having both a standard and extra-thick option is useful if the flange sits below the finished floor. We prefer placing the wax ring on the underside of the toilet bowl for easier alignment.

Lay the bowl on a towel and press the wax ring onto the outlet on the bottom so it stays in place when you lift the bowl.

Step 6: Place The Toilet Bowl

Carefully lower the bowl onto the flange so the floor bolts pass through the bolt holes in the base. Remove the rag from the flange first. If the bowl is heavy, get help to guide it into place. Use a pair of drinking straws over the bolts as a visual aid to help align the holes.

Press down on the bowl to compress the wax ring and form a seal. Some people carefully sit on the closed bowl to help seat it evenly. If placement is wrong or the wax ring deforms, remove the bowl and use a new ring—do not reuse a deformed ring.

Step 7: Bolt The Toilet Bowl

With the bowl seated, add washers and nuts to the floor bolts and hand-tighten. Alternate tightening between bolts a little at a time to maintain even pressure and avoid cracking the porcelain. Trim excess bolt length with a hacksaw and snap on plastic caps when finished.

Step 8: Install The Toilet Tank

Position the tank on the bowl, aligning the large rubber gasket with the outlet hole. Install the tank bolts, rubber washers, and nuts, hand-tightening first and then using a wrench and screwdriver to secure them evenly. Alternate tightening to keep the tank level and avoid cracking.

Step 9: Connect The Water Line

Reconnect the supply line to the tank and hand-tighten. Optionally use plumber’s tape on threads. Slowly open the shut-off valve and let the tank fill. Flush and check for leaks at the supply connection, around the tank bolts and gaskets, and under the bowl near the wax ring. Tighten fittings or replace damaged gaskets as needed. If you find a leak under the bowl, the wax ring likely needs replacing.

Step 10: Finish The Toilet Installation

Attach the toilet seat and make any final adjustments to the tank’s flushing mechanism. Run a few test flushes to confirm proper operation. Finish by applying a neat bead of white silicone caulk around the base of the toilet for a clean look and added sanitary protection.

Bonus Step: Get Rid Of Your Old Toilet

Don’t toss a usable old toilet. Consider donating it to a local charity or selling it locally after a good cleaning. Rehoming reusable fixtures keeps them out of the landfill and can help someone else complete a project.

Toilet Installation FAQs

Other Toilet How-Tos

If you enjoyed this guide, other useful topics include choosing a favorite model, fixing a rocking toilet, converting to dual flush, or troubleshooting clogs and backups.