How to Install a Toilet: Step-by-Step Guide for Beginners
Replacing a toilet is one of the few plumbing jobs a beginner can finish in an afternoon. The parts are simple: a flange, a wax ring, two closet bolts, and a supply line.
The job goes wrong when the flange is broken, the bowl sits unlevel, or the tank bolts leak. This guide walks through the order that keeps those problems from happening. For the wider set of fixture jobs, see the plumbing installation guide.
For the complete overview, read Plumbing Installation Guide: How to Install Fixtures, Appliances, and Pipes Safely.
| Time | About 2 to 3 hours for a standard two-piece toilet |
|---|---|
| Skill level | Beginner, with basic hand tools |
| Shutoff | Close the angle stop and flush the tank empty |
| Wax ring | Use a new ring every time the bowl comes up |
| Flange | Must be clean, flat, and level with the floor |
| Leak check | Flush several times and watch the base and supply |
Gather Tools and Measure the Rough-In
You need a putty knife, adjustable wrench, bucket, new wax ring, closet bolts, and a tape measure before you start.
Measure from the finished back wall to the center of the closet bolts. That number is the rough-in. Most homes use a 12 inch rough-in, but 10 and 14 inch bowls exist.
Buy a toilet that matches the rough-in, or the tank will hit the wall or leave a gap. Have rags and a plastic bag ready for the old wax ring.
Remove the Old Toilet
Shut off the water, drain the tank and bowl, then unbolt the bowl from the flange and lift it straight up.
Close the angle stop behind the toilet and flush. Sponge out the remaining tank water. Disconnect the supply line and unbolt the tank from the bowl.
Pry off the decorative caps and unscrew the closet bolts. Rock the bowl gently to break the wax seal, then lift it with your legs, not your back. Scrape the old wax off the flange.
- Shut off the water and flush the tank dry
- Disconnect the supply line and remove the tank
- Unscrew the closet bolts and cut the old caulk
- Lift the bowl straight up and set it aside
- Scrape the flange clean and check for cracks
Set the Wax Ring and Drop the New Bowl
Press a new wax ring onto the flange or the bowl horn, then lower the bowl over the closet bolts and press it down evenly.
Set the closet bolts in the flange slots so they point straight up. If the flange sits below the floor, use an extra thick wax ring or a flange extension.
Lower the bowl so the bolt holes line up, then press down with steady weight. Do not rock it. The wax should compress once. If you lift the bowl after it seats, replace the ring.
Bolt the Bowl and Check for Level
Tighten the closet bolts with a wrench until the bowl stops moving, then check level and shim any gaps.
Tighten the nuts alternately, a little at a time. Porcelain cracks when one side is tight and the other is loose. Stop when the bowl no longer shifts.
If the bowl rocks, slide plastic shims under the low side and snap them off. A level bowl keeps the wax seal even and prevents leaks at the base.
Connect the Supply, Tank, and Test
Bolt the tank to the bowl, connect the supply line, open the stop, and flush several times while watching for drips.
Set the tank on the bowl and tighten the tank bolts just snug. Over-tightening cracks the tank. Connect the supply line hand tight plus a quarter turn.
Open the angle stop and let the tank fill. Check the supply connections and the base for water. Flush five times, then caulk the base if your local code allows it.
- Bolt the tank to the bowl and snug the nuts
- Attach the supply line to the fill valve
- Open the angle stop and fill the tank
- Flush several times and dry the base
- Check for leaks at the supply, tank, and floor
Frequently asked questions
Can I install a toilet on a broken flange?
No. A cracked flange will not hold the closet bolts or seal the wax ring. Repair it with a flange repair ring or replace the flange before setting the bowl.
How tight should closet bolts be?
Tight enough that the bowl does not move, and no more. Tighten both nuts evenly and stop the moment the bowl feels solid, because porcelain cracks easily.
Do I need a plumber for a toilet install?
Most homeowners can do it. Call a plumber if the flange is broken, the floor is rotted, or the drain line needs to move.
