How to Install a Toilet: Replace a Toilet in 1 Hour (DIY)

Replacing a toilet is the home repair that intimidates people the most — and pays back the most once you've done it once. The job itself is straightforward: it's heavy lifting, not technical plumbing. Most homeowners can complete a standard replacement in under two hours with a wrench, a bucket, and a $12 wax ring. Here is the complete sequence, including the inspection steps most guides skip that save you from discovering a real problem mid-job.

Before You Start: Read These Warning Signs

Not every toilet replacement is a simple swap. Slow down before you begin if any of these conditions exist:

• The toilet has been rocking or shifting. A rocking toilet means the wax ring seal has likely been compromised and water has been leaking at the base — possibly for years. Expect to find damaged subfloor, a corroded flange, or both. Budget time and materials for subfloor repair.
• There's a sewer gas smell in the bathroom. Failed wax ring, cracked flange, or a dry P-trap. The wax ring replacement fixes the first two — but identify the source before assuming.
• The floor feels soft or spongy near the toilet base. Water has been leaking under the floor. You likely have subfloor rot that must be repaired before the new toilet goes in. This turns a 1-hour job into a weekend project.
• The shutoff valve behind the toilet is original (more than 20 years old) or shows mineral buildup. Old shutoff valves seize when turned, then leak when you try to force them. Replace the shutoff valve before replacing the toilet — it's a $15 part and a 30-minute job with the main water off.

If any of those apply, deal with them first. A toilet replacement on a compromised base is just postponing a bigger repair.

Toilet Cost: What You're Buying

The toilet itself is the biggest variable in your budget. Per Angi's 2026 Toilet Cost Report, toilet prices range from $100 for basic builder-grade two-piece units to $800–$2,000+ for comfort-height, elongated, dual-flush, and smart toilet models. Most homeowners replace with a mid-range unit ($200–$450) that offers better performance than the original builder-grade install.

Rough-in measurement: Before buying, measure the distance from the wall (behind the toilet, not baseboard) to the center of the toilet bolts. Standard is 12". Older homes sometimes have 10" or 14" rough-in. Buy a toilet that matches your rough-in — most toilets are 12" but always verify the spec sheet before purchasing.

Materials and Tools Checklist

Materials ($30–$80 Total)

• Wax ring: $8–$20. Standard or with plastic horn extension. When in doubt, buy the horn version.
• Toilet bolt set (closet bolts): $5–$12. Usually included with the toilet; buy separately if not — never reuse old corroded bolts.
• Flexible water supply line (12"): $8–$20. Braided stainless steel only — never rubber or plastic. Even if the old one looks fine, replace it if it's been on for more than 5 years.
• Plumber's putty or silicone caulk: $5–$10. For caulking around the base (optional but recommended).
• Teflon (PTFE) tape: $3–$5. Wrap threaded connections on the supply line shutoff valve threads.
• Plastic shims (toilet shim set): $5–$8. For leveling a toilet on an uneven floor.

Tools Needed

• Adjustable wrench or channel-lock pliers
• Putty knife (for old wax removal)
• Sponge and bucket (for removing remaining water from tank and bowl)
• Hacksaw or bolt cutters (for corroded closet bolts that won't loosen)
• Level (4-foot for checking floor; torpedo level for quick checks)
• Utility knife (for cutting old caulk bead)
• Shop vacuum (optional but makes cleanup much faster)
• Gloves and old towels

Step-by-Step: How to Remove the Old Toilet

Step 1: Shut Off the Water and Disconnect

Turn the shutoff valve clockwise until it stops. Flush the toilet once to empty the tank. Hold the flush handle down to get as much water out as possible. Use a sponge to remove the remaining 1–2 cups of water from the tank and bowl — the bowl always has some residual water that won't flush out. A shop vacuum makes this faster. Place old towels on the floor around the base.

Disconnect the supply line from the bottom of the tank — it's hand-threaded; use pliers for the last quarter turn. Have a rag ready for any remaining water in the line. Cap the shutoff valve end with a rag.

Step 2: Disconnect the Tank (Two-Piece Toilets)

Two-piece toilets have the tank bolted to the bowl — remove the tank first to reduce weight. Inside the tank, remove the two tank bolts (plastic wingnuts on the bottom; hold the bolt head inside the tank with a screwdriver while loosening). Lift the tank straight up and set it in the tub or on a towel. One-piece toilets: skip this step, but plan for a heavy lift — one-piece toilets typically weigh 60–100+ lbs.

Step 3: Remove the Bowl

Cut or peel any caulk around the base with a utility knife. Remove the plastic caps covering the floor bolt nuts — they usually pry off with a flathead screwdriver. Remove the nuts from the closet bolts. If nuts are corroded and won't turn, cut the bolts with a hacksaw below the nut — you're replacing the bolts anyway.

Grip the bowl at both sides (not the tank connection point) and lift straight up with your legs, not your back. The wax ring will grip slightly — a gentle rock side-to-side breaks the seal. Have a helper if you can — a full toilet bowl weighs 60–80 lbs.

Set the toilet on its side on cardboard or a drop cloth to protect the floor. Stuff a rag into the open drain flange immediately — sewer gases are unpleasant and the rag prevents tools or hardware from falling in.

Step 4: Inspect the Flange — The Most Important Step

Remove the old wax ring from the flange and toilet horn with a putty knife — it all comes off. Now examine the flange carefully:

• Flange height relative to finished floor: The top of the flange ring should be at floor level or up to 1/4" above it. If new flooring was installed after the original toilet, the flange may now be below floor level — use a flange extender kit to raise it.
• Flange integrity: Look for cracks, breaks, or missing sections of the ring. A damaged flange ring can often be repaired with a stainless steel repair ring ($15–$35) that overlaps the damage and provides new bolt slots.
• Subfloor condition: Look and feel around the base of the flange for soft or discolored wood — this indicates past water damage. Minor damage (less than 2" around the flange) can be treated and left; anything larger should be repaired before reinstalling the toilet.
• Closet bolt slots: The bolts should sit in T-shaped slots in the flange. If the slots are broken, the repair ring fixes this too by providing new slots.

Step-by-Step: How to Install the New Toilet

Step 5: Set the Closet Bolts

Slide new closet bolts into the T-slots on the flange so they stand perpendicular to the wall. Slide a plastic retainer washer over each bolt to keep them upright while you position the toilet. The bolts should be equidistant from the wall and aligned with each other — measure from the wall to each bolt and adjust if needed. Standard placement is 12" from the finished wall, centered on the drain.

Step 6: Choose and Place the Wax Ring

The wax ring creates the seal between the toilet horn (the opening on the bottom of the bowl) and the drain flange. It's a one-time-use component — never reuse an old wax ring, even if it looks intact.

Wax ring selection: Standard wax ring for flanges at floor level. Wax ring with plastic horn extension when the floor is 1/4" or more above the top of the flange — the horn bridges the gap. When in doubt, buy the horn version and trim if needed. A wax ring that's too thick is better than one that's too thin.

Place the wax ring on the flange (wax side up, plastic horn if present pointing down into the drain). Some plumbers prefer to stick the ring to the toilet horn instead — either method works, but placing it on the flange is easier to position correctly.

Step 7: Set the Toilet Bowl

Lower the toilet bowl straight down onto the flange, aligning the holes in the base with the closet bolts. This requires looking down over the toilet at the bolt locations — have a helper watch from the side to guide alignment. Once the bolt tips appear through the holes, press the toilet firmly and evenly downward — you are compressing the wax ring, and this compression creates the seal.

Do not rock the toilet side-to-side after the wax ring contacts the flange — lateral movement breaks the seal. Set it straight down and press. Once set, the toilet should not rock. If it does rock, the floor is uneven — shim with plastic toilet shims at the low side before moving forward.

Step 8: Tighten Floor Bolts — Carefully

Thread a washer and nut by hand onto each closet bolt. Tighten evenly, alternating sides — right side quarter turn, left side quarter turn — exactly like torquing a cylinder head. Continue until snug, then add one final quarter turn per side with a wrench. Stop there.

Vitreous china (the material toilets are made from) is a ceramic and cracks under excessive clamping force. If you over-tighten and crack the base, the toilet is destroyed — there is no repair. If the toilet still rocks slightly after tightening to spec, add more shims rather than more torque on the bolts. Cut closet bolts to 1/2" above the nut with a hacksaw, then snap on the decorative plastic caps.

Step 9: Install the Tank (Two-Piece Toilets)

Place the rubber spud gasket (large donut-shaped gasket, usually included with the toilet) over the flush valve tailpiece on the bottom of the tank. Lower the tank onto the bowl, aligning the tank bolt holes. Thread tank bolts through the bottom of the tank, through the bowl, and hand-tighten the plastic wingnuts. Again: snug plus a quarter turn — tank bolts also crack the china if overtightened. The tank should not rock or shift when you press on it.

Step 10: Connect the Water Supply

Connect the braided stainless supply line from the shutoff valve to the fill valve inlet on the bottom of the tank. Thread by hand first to verify you're not cross-threading, then snug with pliers — supply line connections are typically hand-tight plus 1/4 turn. Don't wrap the fill valve threads with Teflon tape — the connection uses a rubber washer seal, not thread seal.

Step 11: Test — Slow Turn, Watch Carefully

Turn the shutoff valve counterclockwise slowly — not all at once. As the tank fills, watch all connection points for drips: shutoff valve body, supply line connections at both ends, and around the base of the tank where it meets the bowl.

Once the tank fills, flush and immediately watch the base of the toilet — any water appearing around the base indicates a failed wax ring. If this happens, the toilet must come up and the wax ring replaced.

Also flush twice rapidly to test the flush mechanism and check that the tank refills properly within 60–90 seconds (WaterSense standard: 1.28 gallons per flush in 60 seconds).

Step 12: Caulk the Base

Caulking the toilet base is optional in some jurisdictions and required in others (the 2021 International Plumbing Code requires it for most installations). My approach: apply silicone caulk around three sides of the base, leaving the back open as a leak indicator. Match the caulk color to the toilet (typically white) and smooth with a wet finger or caulk tool. Do not use painter's tape on a toilet base — the curved surface never seals cleanly with tape.

Toilet Replacement Cost: DIY vs. Hiring a Plumber

Per Angi's 2026 Toilet Installation Cost Report, plumbers charge $150–$400 in labor for a standard toilet replacement on existing plumbing. Most plumbers complete the job in 45–90 minutes. The DIY version costs the same materials ($30–$80 in supplies) with zero labor cost — and once you've done it once, your second replacement takes under 45 minutes.

When to Call a Plumber Instead

Not every toilet replacement should be a DIY job. Call a licensed plumber when:

• The flange is broken below the floor or at the pipe connection. Requires cutting into the floor and working on the drain stack — not a DIY job.
• You need to move the drain location. Changing rough-in from 12" to 10" or 14" requires cutting and relocating the drain pipe.
• Installing a wall-mounted toilet. Requires a carrier frame inside the wall connected to the drain — this is a full rough-in job.
• Installing an upflush/macerating toilet (basement application). These connect to existing drain lines at different points and have specific installation requirements.
• The shutoff valve is in a wall or the main house valve cannot be located. A plumber can add or move shutoff valves efficiently.

For a full bathroom renovation context, see our Bathroom Remodel Cost Guide — toilet replacement is one of the simpler line items in a full remodel scope.

Frequently Asked Questions