How to Install a New Toilet (2-Hour Replacement Guide)
Replace a toilet in 2-3 hours for $150-280 in parts. Every step from shutting off the water to the final test flush, including the one wax ring mistake to avoid.
Quick answer: Installing a new toilet takes 2-3 hours and costs $150-280 for a budget-to-midrange toilet plus the wax ring ($5-8), closet bolts ($3-5 if not included), and a braided supply line ($10-15). Shut off the water, flush the tank empty, disconnect the supply line, rock and lift the old toilet, scrape off the old wax ring, set new closet bolts and a fresh wax ring on the new bowl, lower it straight onto the flange once, snug down the nuts without overtightening, connect the tank and supply, then run a test flush.
The most common reason people call a plumber for a toilet swap is the weight, not the complexity. At 60-80 pounds of porcelain, a toilet bowl is awkward to set down without cracking it on the floor tile. That’s the actual hard part of this job.
Everything else is methodical work with basic hand tools. No soldering, no pipe threading, no specialty equipment. A second person helps for the moment you’re lowering the bowl onto the flange. The rest of the job is doable solo.
What You’ll Need
Tools:
- Adjustable wrench
- Channel-lock pliers
- Putty knife or plastic scraper
- Utility knife
- Hacksaw (for trimming closet bolts)
- Level
- Sponge and bucket
- Shop vac (helpful, not required)
Supplies:
- New toilet
- Wax ring (standard for most floors; extra-thick if the floor flange sits low)
- New closet bolts, if not included with the toilet (around $4 at any hardware store)
- 12” or 16” braided stainless steel supply line, depending on distance to shut-off valve
- Plastic toilet shims
- Old towel or cardboard to protect the floor
Step 1: Shut Off the Water and Empty the Tank
Turn the shut-off valve behind the toilet clockwise until it stops. If the valve is old and stiff, shut off the main water supply before forcing a corroded valve and making a different problem.
Flush the toilet and hold the handle down a few extra seconds to clear as much water as possible. Sponge out what stays in the tank until it’s mostly dry. The bowl will still have water in the trap, which drains when you lift the old toilet off the flange.
Step 2: Disconnect the Old Toilet
Unscrew the supply line from the bottom of the tank. Have a rag ready for the small amount of water that drains from the line.
Pry off the plastic caps at the base of the toilet with a flathead screwdriver. Loosen the nuts on the closet bolts underneath, one on each side of the base. If the nuts are corroded and won’t turn, cut the bolts with a hacksaw below the nut level.
Grab the bowl at the rim on both sides (not the tank), rock it gently front to back to break the wax seal, then lift straight up. Set it down on cardboard or a folded towel so you’re not resting porcelain on tile. For a two-piece toilet, removing the tank first makes the bowl lighter and easier to handle.
Stuff a rag into the floor drain opening to keep sewer gas out while you work.
Step 3: Remove the Old Wax Ring and Check the Flange
The wax ring is a yellowish waxy disc. It comes off in sticky pieces with a putty knife. Scrape both the flange surface and the bottom of the old toilet if you’re examining it.
Look at the flange. It should sit flush with or slightly above the finished floor surface. If the flange surface is more than a quarter inch below the floor (common when tile has been added over original flooring), you need an extra-thick wax ring or a wax ring with a plastic horn extension. A standard ring on a low flange creates a gap that will leak.
Check the flange for cracks or broken mounting slots. A damaged flange needs repair before the new toilet goes in. And check the subfloor around the drain. Any soft spots, dark discoloration, or sponginess means water damage that should be addressed before you set a new toilet on it.
Step 4: Set the New Closet Bolts and Wax Ring
Slide new closet bolts into the slots on the floor flange, one on each side, positioned so they stand upright. Most toilets include closet bolts in the hardware bag. If yours didn’t, they’re a $3-4 item.
Press the wax ring onto the bottom of the new toilet bowl, wax side down, centered on the horn (the outlet opening at the bottom of the bowl). Some installers prefer pressing the ring onto the flange instead. Both work as long as you only set the toilet down once.
Step 5: Lower and Seat the Toilet
This is where a second person is worth having. Lift the toilet, line up the holes in the base with the closet bolts, and lower it straight down onto the flange. Press down with your full body weight to compress the wax ring. The toilet base should contact the floor without rocking.
Don’t lift the toilet back up to check positioning. Once the wax ring seats, it’s done. Repositioning means buying a new ring.
Slide the plastic and metal washers over the bolts, then thread the nuts by hand. Snug them down alternating sides, same as lug nuts on a wheel. Get them firmly hand-tight, then go about a quarter turn more with a wrench. That’s the ceiling. Porcelain cracks under too much torque, and a hairline crack in the base won’t announce itself until it becomes a real crack. If the toilet still rocks slightly after tightening, add plastic toilet shims under the low side, then trim the shims flush with a utility knife.
Cut the closet bolts with a hacksaw flush with the nuts, then press the plastic caps into place.
Step 6: Install the Tank (Two-Piece Toilets)
Set the rubber gasket onto the bottom of the tank (it goes between the tank and the bowl). Lower the tank onto the bowl and run the tank-to-bowl bolts through the rubber washers from inside the tank. Tighten from underneath, alternating sides. Same rule as the base bolts: snug, not cranked.
One-piece toilets skip this step entirely.
Step 7: Connect the Water Supply and Test
Thread the new braided supply line onto the fill valve at the bottom of the tank, hand-tight plus a half-turn with pliers. Connect the other end to the shut-off valve the same way.
Open the shut-off valve slowly and watch both connection points while the tank fills. Stay in the room for the first fill. Once the tank is full, flush and watch the base, the tank bolts, and the supply line connections for any drips.
Standard plumbing practice is to leave a small gap at the back of the toilet base uncaulked. If the wax ring ever fails, that gap lets water appear at floor level where you’ll see it, rather than seeping silently into the subfloor for months. Caulk the front and sides for a clean look, and leave the back open. The International Plumbing Code and most toilet manufacturers, including Kohler, specify this same approach.
For a running toilet after installation or a fill valve that cycles on and off, those guides walk through the adjustments. A brand-new fill valve usually just needs the float arm repositioned to set the right tank water level.
Common Mistakes
Overtightening the closet bolt nuts. Porcelain cracks under too much pressure. A toilet that still rocks after tightening has a floor problem, not a loose-bolt problem. Cranking the nuts harder doesn’t fix a floor that isn’t flat.
Setting the toilet twice on the same wax ring. The ring is designed to seat once. If you lower the toilet, notice it’s off-center, and lift it back up, you need a new wax ring before proceeding. A compressed or smeared wax ring will not seal.
Reusing the old wax ring. They’re $5-8. Don’t.
Using the wrong ring thickness. Standard for a flange at or above floor level. Extra-thick for a flange that’s been buried by tile or otherwise set low. Using the thick ring when the flange is at floor level props the toilet up and creates a wobble that tightening bolts can’t fix.
Not checking for a wobbly toilet right after installation. If the base rocks before the bolts are tight, something is off. Add shims before you leave the bathroom. A rocking toilet destroys a wax ring faster than anything else.
Caulking all the way around the base. Leave the back open so any future leak shows up at floor level instead of draining into the subfloor.
When to Call a Pro
The toilet itself is homeowner territory. The floor flange sometimes isn’t. A cracked cast iron flange, a flange that’s significantly below floor level without a riser, or rotted subfloor around the drain are situations where a licensed plumber is the right call. Floor joist damage under a bathroom is a structural repair, not a plumbing repair, and you want someone who can pull a permit.
If the flange is intact and the floor is solid, you can handle the rest.
FAQ
How long does it take to install a new toilet? First time, plan on 2-3 hours. Most of that is working at a deliberate pace and letting things drain between steps. If you’ve done a toilet swap before, 90 minutes is realistic.
What size wax ring do I need to install a toilet? Standard (3” or 4” ID depending on your toilet’s horn) for most installs. Extra-thick, sometimes labeled “double wax” or with a plastic horn extension, if the floor flange sits more than a quarter inch below the finished floor. Check the flange height before going to the hardware store.
How much does it cost to install a new toilet yourself? Budget models like the American Standard Cadet 3 run around $120-150. Mid-range toilets like the Kohler Cimarron or American Standard Champion 4 cost $200-300. High-end models with bidet seats or skirted bases push $400 and up. Add $25-35 for the wax ring and braided supply line. Plumber labor for a straightforward swap typically runs $150-300 depending on your market.
Do I need to caulk around the base of the toilet? Front and sides yes, back no. The gap at the back lets any wax ring failure appear as visible water at floor level instead of seeping silently into the subfloor. Kohler’s own installation instructions specify this same approach.
Can I reuse my old toilet seat on a new toilet? Yes, if the bolt hole spacing matches. Standard residential toilets use 5.5-inch center-to-center bolt spacing, which fits most seats. Measure the old seat to confirm before assuming it fits.
Why is my new toilet rocking after installation? Either the floor is slightly uneven at the base, the wax ring didn’t fully seat, or the closet bolts worked loose. Add plastic toilet shims under the low side, trim them flush, and caulk over them. Don’t keep tightening the closet bolts to compensate for a rocking toilet; you’ll crack the base before you fix the wobble.
Is this a good time to replace the fill valve and flapper? If the toilet is more than 10 years old, yes. A new fill valve runs $12-15 and a flapper costs $5-8. Both are cheap enough to swap while the water is already off, particularly if the old components look worn or discolored.
How do I know if the wax ring sealed correctly? Press down with your body weight when setting the bowl, and snug the closet bolt nuts evenly. If the toilet sits flat without rocking before the nuts are tightened, the ring is almost certainly seated right. Run several test flushes and check the base for moisture. A failed seal shows up at floor level pretty quickly.
Wrapping Up
A toilet replacement is straightforward once you understand that the wax ring is the one step you can’t redo without buying a new part. Take that step deliberately, lower the bowl straight down, and the rest of the job is standard plumbing.
The EPA’s WaterSense program estimates replacing a pre-1994 toilet (3.5 gallons per flush) with a current WaterSense model (1.28 gpf) saves roughly 13,000 gallons of water per year per household toilet. In areas with tiered water rates, the payback on a new toilet adds up faster than you might expect.
For every other toilet issue you might run into after the installation, the complete toilet repair guide has you covered.