How to Replace a Toilet
Remove your old toilet and install a new one, including connecting the water supply and setting a new wax ring seal. This project requires moderate physical effort but no special plumbing license in most jurisdictions.
What You'll Need
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Tools
Adjustable wrench
For tightening and loosening supply line nuts and tank bolts
Channel-lock pliers
For gripping large nuts such as the water supply coupling and closet bolt nuts
Putty knife or scraper
For scraping old wax residue off the floor flange
Hacksaw or bolt cutters(optional)
For cutting corroded closet bolts that won't unscrew
Utility knife
For scoring old caulk around the toilet base
Bucket and sponge
For removing standing water from the tank and bowl
Wet/dry vacuum(optional)
Speeds up removing water from the bowl and trap
Rubber gloves
Heavy-duty, elbow-length preferred for sanitation when handling the old toilet
Safety glasses
Protects eyes when cutting bolts or scraping flange
Tape measure
For measuring rough-in distance before purchasing a new toilet
Level
For confirming the toilet sits plumb after installation
Materials
Replacement toilet
Two-piece or one-piece; confirm rough-in distance (typically 12 inches from wall to center of flange) before buying
$90-$500
Wax ring
Standard wax ring or wax-free gasket; if your flange sits below finished floor level, use an extra-thick ring or a flange extender - a horned ring is optional extra insurance for a normal-height flange
$5-$20
Closet bolts (toilet bolts)
5/16-inch stainless steel T-bolts that anchor the toilet to the floor flange; often included with new toilet
$4-$10
Braided stainless steel supply line
12- to 16-inch flexible supply line with 3/8-inch compression x 7/8-inch ballcock nut; replace any time you replace a toilet
$5-$15
Toilet seat
Elongated or round to match bowl shape; may or may not be included with toilet
$15-$100
Silicone caulk (white or clear)(optional)
Paintable silicone or siliconized latex for sealing the toilet base to the floor; leave rear uncaulked to allow leak detection
$5-$12
Plastic toilet shims(optional)
For leveling the toilet on an uneven floor
$3-$8
Penetrating oil (e.g. WD-40)(optional)
For loosening corroded closet bolt nuts
$5-$10
Flange extender kit or stainless flange repair ring(optional)
Only needed if inspection shows the closet flange is cracked or sits more than 1/4 inch below the finished floor.
$5-$25
Step-by-Step Instructions
Measure the rough-in distance and purchase the correct toilet
10-15 minutes
Before buying a new toilet, measure the rough-in: the distance from the finished wall (not the baseboard) to the center of the floor drain flange bolts. Most homes use a 12-inch rough-in; older homes may use 10 or 14 inches. Write down this measurement and whether your bowl is round (about 16.5 inches front to back) or elongated (about 18.5 inches) to confirm the new toilet will fit your space.
Pro Tip
If you cannot see the flange bolts because the toilet is still in place, measure from the wall to the center of the capped bolt covers on either side of the base instead.
Shut off the water supply to the toilet
5-10 minutes
Locate the angle stop shut-off valve on the wall or floor directly behind and below the toilet tank. Turn the handle clockwise until it stops. Flush the toilet once to drain the tank, then hold the flush handle to empty as much water from the bowl as possible. Use a sponge and bucket or a wet/dry vacuum to remove the remaining water from both the tank and the bowl until they are dry.
Pro Tip
If the angle stop valve is corroded and won't turn, shut off water at the main house shutoff and plan to replace the angle stop while you have things apart.
Warning
Do not skip draining the tank and bowl. Lifting a toilet full of water adds 20-40 lbs and risks spilling sewage water on your floor.
Disconnect the water supply line
3-5 minutes
Place a small towel or bucket under the supply line connection at the bottom of the tank. Use channel-lock pliers to hold the ballcock nut (the larger plastic or metal nut at the underside of the tank) still while you unscrew the supply line coupling nut counterclockwise with an adjustable wrench. Once disconnected, let any residual water drain into the bucket. Set the old supply line aside - you will discard it and install a new one.
Pro Tip
Always replace the supply line when replacing a toilet. Old braided lines are a common source of slow leaks and catastrophic failures.
Remove the toilet tank (two-piece toilets only)
5-10 minutes
If you have a two-piece toilet (separate tank and bowl), remove the tank first to reduce weight. Unscrew the two tank bolt nuts located inside the tank near the bottom - use a flathead screwdriver to hold the bolt head still while you turn the nut counterclockwise with a wrench. Lift the tank straight up off the bowl and set it on a towel or cardboard to protect the floor. Skip this step for one-piece toilets.
Pro Tip
Tank bolts are often rubber-gasket sealed and may spin freely; pinch the rubber washer against the tank bottom with your fingers while turning the nut.
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Track This Project FreeRemove the toilet bowl
10-15 minutes
Pry off the decorative plastic caps at the base of the toilet on each side to expose the closet bolt nuts. If the nuts are corroded, spray penetrating oil and wait 5 minutes. Use channel-lock pliers to unscrew the nuts counterclockwise, then remove the washers and nuts. Score any caulk around the base of the toilet with a utility knife. Rock the toilet gently from side to side to break the wax seal, then lift it straight up and set it on cardboard or an old tarp. Do not tilt it - remaining water in the trap will spill.
Warning
Toilets weigh 50-100 lbs. Have a helper or use proper lifting form (bend knees, keep back straight) to avoid injury. The wax ring is contaminated with sewage - wear rubber gloves and avoid contact with skin.
Clean the floor flange and inspect for damage
10-15 minutes
Use a putty knife to scrape all old wax residue off the floor flange, removing every trace so the new wax ring seats properly. Stuff a rag into the drain opening to block sewer gases while you work. Inspect the plastic or cast-iron flange ring for cracks, breaks, or corrosion. The top surface of the flange should sit at or slightly above the finished floor level. Check that the flange bolt slots are intact and can hold a T-bolt securely.
Pro Tip
If the flange is cracked but the drain pipe is intact, a stainless steel repair ring can be installed over the existing flange without breaking up the floor - a much easier fix than full flange replacement.
Warning
A broken or sunken flange that cannot be repaired with a repair ring requires professional assessment. Installing a toilet over a damaged flange can result in leaks under the floor, structural damage, and mold.
Set the new closet bolts
3-5 minutes
Slide two new stainless steel T-bolts (also called closet bolts) into the slots on opposite sides of the flange, with the flat T-head seated flat in the slot so the threaded shaft points straight up. Space them so they are centered on the flange and aligned front-to-back with where the toilet will sit. Most flanges have alignment marks; if yours does not, set the bolts parallel to the wall behind the toilet.
Pro Tip
Some kits include plastic bolt keepers that clip onto the flange to hold the bolts upright while you lower the toilet - use them if provided. They make toilet placement much easier.
Install the wax ring
3-5 minutes
Remove the rag from the drain opening just before this step. Press the new wax ring onto the underside of the toilet horn (the molded drain outlet on the bottom of the bowl). If the ring has a plastic horn/funnel, orient it so the funnel faces down toward the drain. Do not reuse the old wax ring under any circumstances.
Pro Tip
Warm wax seals better - if your bathroom is cold, set the wax ring in a warm room for 10-15 minutes before installation. For wax-free gaskets, follow the manufacturer's orientation instructions printed on the packaging.
Warning
You only get one shot at seating the wax ring correctly. Once the toilet touches the wax, do not lift it again - lifting breaks the seal and requires a new ring.
Lower and seat the toilet bowl
5-10 minutes
With a helper if possible, lift the toilet bowl and position it directly over the flange so the two holes in the base align with the two upright T-bolts. Lower the toilet slowly and steadily, keeping it level, until it makes contact with the floor. Press down firmly and evenly with your body weight - sit on the toilet or press both hands on the rim - to compress the wax ring fully into the flange. The base should rest flat on the floor with no rocking. Do not twist or lift the toilet once it has touched the wax.
Pro Tip
Thread a nut loosely onto each bolt first so you can confirm alignment before fully pressing down.
Warning
If the toilet rocks after seating, do not caulk over the gap or force it flat. Rocking means the wax ring did not seat evenly or the floor is uneven - use plastic toilet shims to stabilize the base before tightening bolts.
Secure the toilet to the floor with closet bolt nuts
10-15 minutes
Place a metal washer over each bolt, then thread a closet bolt nut onto each bolt by hand. Use channel-lock pliers to tighten each nut, alternating sides (left a few turns, then right a few turns) to keep even pressure, similar to tightening lug nuts on a wheel. Tighten until the toilet base is firm against the floor with no rocking - do not overtighten, as ceramic can crack. The bolts will likely extend above the nuts; use a hacksaw or close-quarter bolt cutter to trim them so roughly 1/4 inch of thread remains above the nut. Press the plastic caps over the nuts to finish.
Pro Tip
Check for rocking by pressing down on each front corner of the toilet. If one side lifts, insert a plastic toilet shim at that corner, tap it in gently until snug, then score off any protruding shim with a utility knife.
Warning
Overtightening closet bolt nuts is one of the most common causes of cracked toilet bases. Stop tightening when the toilet is stable - snug, not cranked.
Install the tank on the bowl (two-piece toilets only)
10-15 minutes
Before lowering the tank, seat the large rubber spud gasket (tank-to-bowl gasket) over the flush valve opening on the underside of the tank - without it the tank will leak at every flush. Orient the tank so the flush valve (the large rubber flapper assembly at the bottom of the tank) aligns with the water inlet hole at the back of the bowl. Lower the tank straight down onto the bowl, guiding the two rubber tank bolt washers through the holes in the bowl. From underneath the bowl rim, place a metal washer over each bolt and thread on the plastic or brass nuts by hand. Tighten the nuts alternately (left, right, left, right) with a wrench until the tank is level and does not wobble - a quarter-turn past hand-tight is usually sufficient. Skip this step for one-piece toilets.
Pro Tip
Sit on the bowl and look into the tank as you tighten to watch the rubber washers compress - stop when you see them flatten slightly against the bowl porcelain.
Warning
Porcelain cracks easily under uneven pressure. Never fully tighten one bolt before tightening the other; always alternate.
Connect the water supply line
5-10 minutes
Thread the new braided stainless steel supply line onto the angle stop valve first, tightening the compression nut clockwise by hand, then snug it with channel-lock pliers - a quarter to half turn past hand-tight. Next, connect the other end of the supply line to the ballcock fill valve nut at the bottom of the tank, threading it clockwise by hand, then tightening with a wrench about a half-turn past hand-tight. Do not overtighten either connection; the rubber or nylon washers inside the fittings provide the seal.
Pro Tip
Make sure the supply line has a gentle curve with no kinks - a kinked line restricts flow and can fail prematurely.
Turn on the water and check for leaks
10-15 minutes
Slowly turn the angle stop valve counterclockwise to open it and let the tank fill. Watch the supply line connections at both ends for drips while the tank fills. Once full, flush the toilet and watch the base of the toilet, the wax ring area, and the supply line during and after the flush cycle. Dry all surfaces with a paper towel and inspect again after 5 minutes. A slow leak may not show up immediately - run 3-4 flush cycles and inspect each time.
Pro Tip
Slide a sheet of dry paper towel under the toilet base and check it after several flushes - a damp spot on the paper towel indicates a wax ring leak even if the floor surface looks dry.
Warning
A leak at the base of the toilet after flushing - not condensation - indicates a failed wax ring seal. You must remove the toilet and reseat it with a new wax ring. Do not ignore this: prolonged leaks cause subfloor rot and mold.
Install the toilet seat and apply caulk
10-15 minutes
Thread the seat hinge bolts down through the holes at the rear of the bowl and secure them with the plastic nuts from underneath, hand-tightening or using a wrench per manufacturer instructions. Apply a thin bead of white silicone caulk around the front and sides of the toilet base where it meets the floor, leaving the back side uncaulked so that a future wax ring leak will be visible rather than pooling under the toilet. Smooth the bead with a wet finger. Allow caulk to cure for the time listed on the package before the next use.
Pro Tip
Painter's tape along both sides of the caulk line before applying will give you a clean, professional edge - remove it while the caulk is still wet.
Common Mistakes to Avoid
- Reusing the old wax ring - a used wax ring cannot form a reliable seal and will leak; always install a new one
- Lifting the toilet after it has contacted the wax ring, which breaks the seal and requires starting over with a new ring
- Overtightening the closet bolt nuts or tank bolts, which cracks the porcelain base or tank
- Failing to measure the rough-in distance before purchasing the new toilet, resulting in a return trip to the hardware store
- Caulking all the way around the base of the toilet, which traps wax ring leak water under the toilet and hides damage until it becomes a major subfloor repair
Safety Warnings
- Always shut off the water supply at the angle stop valve before disconnecting any fittings. If the valve fails, know where your main water shutoff is before starting.
- Toilet waste water and residue are a biohazard. Wear heavy rubber gloves for all steps involving the old toilet, wax ring, or flange. Wash hands thoroughly after the job.
- Toilets are heavier than they look (50-70 lbs for the bowl alone). Use proper lifting technique - bend your knees, keep your back straight - and use a helper whenever possible to avoid back injury.
- Sewer gas (hydrogen sulfide and methane) can escape from an open drain. Plug the flange opening with a rag immediately after removing the toilet and remove it only when ready to seat the new wax ring.
When to Call a Professional
Call a licensed plumber if: the floor flange is cracked through or broken off the drain pipe; the subfloor around the toilet is soft, spongy, or visibly rotted (indicating water damage that requires a carpenter or contractor as well); the toilet drain rough-in distance does not match any available toilet size and the drain location may need to move; the angle stop shut-off valve is corroded solid and cannot be closed, requiring main shutoff and valve replacement; or a leak at the base persists after two attempts at reseating with a new wax ring, which may indicate a deeper flange or drain problem.
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Frequently Asked Questions
How difficult is it to replace a toilet?
How much does it cost to replace a toilet?
What tools do I need to replace a toilet?
How long does it take to replace a toilet?
What are common mistakes when trying to replace a toilet?
Should I hire a professional to replace a toilet?
How much does it cost to replace a toilet yourself versus hiring a plumber?
How do I know if I need a 10-inch, 12-inch, or 14-inch rough-in toilet?
Do I need to caulk around the base of the new toilet?
The toilet rocks after I set it down. Can I just tighten the bolts to fix it?
Can I replace a toilet in an afternoon, or is this a multi-day project?
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Project Overview
- Difficulty
- Intermediate
- Time
- 2-4 hours
- Est. Cost
- $120–$600
- Tools
- 11 items
- Materials
- 9 items
- Steps
- 14
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