Toilet Replacement: A Step-by-Step Tool Guide

Tools and Materials You Will Need

Gather everything before you start. A trip to the hardware store mid-project with no working toilet in the house is not ideal. The tool list is short and most items are inexpensive enough to keep permanently in your plumbing tool kit.

• Adjustable wrench or channel-lock pliers for disconnecting the water supply line and removing closet bolt nuts. Channel-locks give better grip on corroded nuts.
• Putty knife for scraping the old wax ring off the flange and toilet base.
• Hacksaw or oscillating multi-tool for cutting corroded closet bolts that won't turn. An oscillating tool with a metal-cutting blade is faster in tight spaces.
• Penetrating oil (PB Blaster or similar) for loosening corroded nuts. Apply it 15 minutes before you try to turn the nut.
• Wet/dry shop vacuum for removing standing water from the tank and bowl after the final flush. A sponge works too, but the vacuum is faster.
• Wax ring (standard or extra-thick depending on flange height), new closet bolts, and a braided stainless steel supply line. Do not reuse any of these.
• Silicone caulk and caulk gun for sealing the base to the floor after installation.
• Plastic shims for leveling the toilet if the floor is uneven.

Removing the Old Toilet

Turn off the water at the shutoff valve behind the toilet. Flush the toilet and hold the handle down to drain as much water as possible from the tank. Sponge out the remaining water from the tank and bowl, or use a wet/dry vacuum. Disconnect the supply line from the bottom of the tank with an adjustable wrench or channel-lock pliers. Have a bucket and towels ready because some water will spill.

Pop the caps off the closet bolts at the base, then remove the nuts. These nuts may be corroded, especially in bathrooms with high humidity. Penetrating oil and patience help. If the nut spins freely without coming off (the bolt is spinning inside the flange slot), grip the bolt with locking pliers while turning the nut. If the nut is completely seized, cut it off with a hacksaw or an oscillating multi-tool with a metal-cutting blade. Replacement closet bolts cost less than a dollar, so do not waste time trying to save them.

Lift the toilet straight up. One-piece units weigh 80 to 100 pounds and are awkward to grip. A two-piece toilet lets you remove the tank first (unbolt it from the bowl) to reduce the weight. Tip the bowl slightly to clear the bolts, then carry it out on its side. Stuff a rag into the open drain flange immediately to block sewer gas while you work. The smell is unmistakable and fills the bathroom quickly.

Flange Inspection and Repair

With the old toilet removed, inspect the flange. The flange is the ring cemented or screwed to the drain pipe that the toilet bolts to. It should be level with or slightly above the finished floor, undamaged, and firmly attached. Grab it and try to rock it. If it moves, the mounting screws need tightening or the flange itself needs replacing.

If the flange is cracked, corroded, or has a broken bolt slot, a repair flange (also called a repair ring) fits over or inside the existing flange and restores the mounting surface. Repair flanges from companies like Oatey and Sioux Chief run $5 to $15 at most hardware stores and install with a few screws. This is a common fix, especially in older homes with cast iron flanges.

Scrape the old wax ring completely off the flange using a putty knife. Get it all. The new wax ring needs a clean, flat surface to seal properly. If the flange sits below the floor surface (common after new flooring is installed over old flooring), use an extra-thick wax ring or a flange extension ring to bridge the gap. The wax must compress between the toilet horn and the flange to create a watertight seal. If the gap is too large for wax to bridge, the seal will fail and you will have sewage seeping around the base.

Setting the New Toilet

Insert new closet bolts into the flange slots and position them equidistant from the wall. Measure from the wall to each bolt to confirm they are centered. Bolts that are off-center pull the toilet to one side and make it harder to seat evenly.

Place the new wax ring on the flange, centered over the drain opening. Some people prefer to press the wax ring onto the bottom of the toilet instead. Either approach works, but placing it on the flange gives you a better view of alignment as you lower the toilet. If you are using a wax ring with a built-in horn (a plastic funnel that extends into the drain), the horn faces down into the pipe.

Remove the rag from the drain. Lower the toilet straight down onto the flange, aligning the holes in the base with the closet bolts. This is the step where a helper makes the biggest difference. You need to guide the bolts through the holes while keeping the bowl centered over the wax ring. Press down firmly with a slight rocking motion to seat the wax ring. Do not lift the toilet once it contacts the wax. If you break the seal, you need a new wax ring. Wax rings are single-use and cost $3 to $8, so keep a spare on hand.

Hand-thread the washers and nuts onto the closet bolts. Tighten alternately: a few turns on one side, a few on the other. This seats the toilet evenly and prevents the base from cracking. Snug is enough. Over-tightening cracks porcelain, and a cracked base means buying a new toilet. If the toilet rocks, do not tighten the bolts further. Shim the base with plastic toilet shims, snap off the excess flush with the base, and caulk over them.

Tank Assembly and Water Line

If you have a two-piece toilet, bolt the tank to the bowl using the hardware included with the toilet. The tank-to-bowl gasket (a large rubber ring) sits between the tank and the bowl and seals the connection. Tighten the tank bolts alternately and evenly, checking that the tank stays level and the gasket compresses uniformly. This is another place where over-tightening cracks porcelain. The gasket does the sealing, not bolt tension. Snug plus a quarter turn is usually right.

Connect the water supply line to the fill valve at the bottom of the tank. Use a new braided stainless steel supply line. These cost $5 to $10 and are far more reliable than the old plastic or chrome-plated lines. Do not reuse the old supply line. Hand-tighten the coupling nut, then snug it a quarter turn with pliers. Do not use pipe tape or pipe dope on this connection. The rubber washer inside the coupling nut creates the seal.

Turn the water on slowly and watch for leaks at three locations: the supply connection at the bottom of the tank, the tank bolts where the tank meets the bowl, and the base where the toilet meets the floor. Flush several times and check again. A leak at the base after flushing indicates a wax ring seal problem. A leak at the tank bolts means the gasket is not compressed evenly. A leak at the supply connection means the nut needs another quarter turn or the washer is misaligned.

Finishing and Troubleshooting

Apply a thin bead of silicone caulk around the base where the toilet meets the floor, leaving a small gap at the back (roughly one inch of uncaulked space). The caulk prevents water from getting under the toilet during floor mopping and gives the installation a clean, finished look. The gap at the back allows any wax ring leak to be visible. Water appearing at the back of the toilet is your first sign of a seal failure, and a fully caulked base hides that warning sign.

If the toilet rocks after installation, do not over-tighten the closet bolts. Instead, shim the base with plastic shims (available in the plumbing aisle for about $2). Slide shims under the base at the rocking points, snap the excess off flush with the base, and caulk over the shims. A rocking toilet will eventually break its wax seal and leak. Fixing the rock now prevents a much messier repair later.

If you see water around the base after flushing, the wax ring is not sealing properly. Pull the toilet, scrape off the failed wax ring, install a new one, and reset the toilet. Wax rings are single-use. Never reuse one, even if it looks intact. A wax-free gasket (like the Fluidmaster Better Than Wax) is a reusable alternative that some homeowners prefer. Manufacturer specs indicate these seal reliably on level flanges but may not perform as well on uneven or recessed flanges.

Shutoff Valve Replacement

While the toilet is disconnected, evaluate the shutoff valve. If the valve is stuck, drips from the stem when you try to close it, or does not fully stop the water flow when closed, replace it during the toilet swap. Doing this work now, while the toilet is already removed, is much simpler than doing it as a separate project later.

A compression-fitting quarter-turn ball valve is the best replacement. Ball valves stop water reliably with a simple lever (a quarter turn from open to closed) and rarely fail. The old multi-turn gate valves common in older homes corrode internally and eventually stop sealing. A quarter-turn ball valve from brands like SharkBite or BrassCraft costs $8 to $15 and installs with a compression fitting that does not require soldering.

Frequently Asked Questions

What Size Wax Ring Do I Need?

Standard wax rings fit most toilets. If your flange is at floor level, a standard ring is fine. If the flange is slightly below the floor (recessed), use an extra-thick wax ring or a wax ring with a built-in horn (a plastic funnel that extends into the drain opening). Wax-free gaskets are an alternative that are reusable and less messy. User reviews report they work well on level flanges but may not seal as reliably on uneven or recessed flanges.

How Do I Know if I Need to Replace the Shutoff Valve?

If the valve is stuck (will not turn), drips from the stem when you try to close it, or does not fully stop the water flow when closed, replace it during the toilet swap. A compression-fitting quarter-turn ball valve is the best replacement. It stops water reliably and operates with a simple lever. Replacing an old multi-turn gate valve while the toilet is already disconnected is much easier than doing it later as a separate job.

Can One Person Install a Toilet?

Yes, but a one-piece toilet weighing 80 to 100 pounds is awkward to lower onto the flange alone. A two-piece toilet is easier because you install the bowl (about 50 pounds) and tank separately. The critical moment is lowering the bowl onto the wax ring and bolts. You need to align the bolt holes while keeping the weight centered. Having a helper guide the bolts through the holes while you lower the bowl makes this significantly easier and reduces the risk of missing the wax ring and needing to start over.

Related Reading

• Bathroom Remodel Tools
• Garbage Disposal Guide