Toilet Replacement: A Step-by-Step Tool Guide

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.

Pop the caps off the closet bolts at the base, remove the nuts (they may be corroded — penetrating oil and patience help, or cut them off with a hacksaw), and lift the toilet straight up. Toilets are heavy and awkward. A one-piece unit can weigh 80 to 100 pounds. Tip it slightly to clear the bolts, then carry it out on its side. Stuff a rag in the open drain flange to block sewer gas while you work.

Flange Inspection and Repair

With the old toilet removed, inspect the flange (the ring cemented to the drain pipe that the toilet bolts to). The flange should be level with or slightly above the finished floor, undamaged, and firmly attached to the floor. If the flange is cracked, corroded, or broken, a repair flange fits over or inside the existing one and restores the mounting surface.

Scrape the old wax ring completely off the flange and the bottom of the old toilet if you're reusing it. A putty knife handles the bulk. The new wax ring needs a clean, flat surface to seal properly. If the flange is below the floor surface (common after new flooring is installed over the old), use an extra-thick wax ring or a flange extension ring to bridge the gap.

Setting the New Toilet

Insert new closet bolts into the flange slots and position them equidistant from the wall. Place the new wax ring on the flange (some people put it on the toilet instead — either works, but on the flange gives you a better view of alignment). Remove the rag from the drain.

Lower the toilet straight down onto the flange, aligning the holes in the base with the closet bolts. Press down firmly with a slight rocking motion to seat the wax ring. Don't lift the toilet once it contacts the wax — if you break the seal, you need a new ring. Hand-thread the washers and nuts onto the closet bolts, then tighten alternately (a few turns on one side, a few on the other) until the base sits firmly on the floor. Don't overtighten or you'll crack the porcelain.

Tank Assembly and Water Line

If you have a two-piece toilet, bolt the tank to the bowl. The tank-to-bowl gasket seals the connection. Tighten the tank bolts alternately and evenly, checking that the tank stays level and the gasket compresses uniformly. Over-tightening cracks the tank. Snug is enough — the gasket does the sealing, not the bolt tension.

Connect the water supply line to the fill valve at the bottom of the tank. A braided stainless steel supply line is the most reliable — don't reuse the old one. Hand-tighten the coupling nut, then snug it a quarter turn with pliers. Turn the water on slowly and check for leaks at the supply connection, the tank bolts, and the base. Flush a few times and check the floor around the base for any seepage that would indicate a wax ring seal problem.

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. Caulk prevents water from getting under the toilet during floor mopping, and 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).

If the toilet rocks after installation, don't over-tighten the bolts — shim the base with plastic shims (snap the excess off flush with the base) and caulk over the shims. A rocking toilet will eventually break its wax seal and leak. If you see water around the base after a flush, the wax ring isn't sealing. Pull the toilet, install a new wax ring, and reset. Wax rings are single-use — never reuse one.

Frequently Asked Questions