How to Replace a Toilet

Turn off the shut-off valve behind the toilet (clockwise). Flush the toilet to empty the tank. Hold the flush handle down to drain as much water as possible. Use a sponge to absorb the remaining water in the tank and bowl. Disconnect the water supply line from the bottom of the tank — have a towel ready to catch drips.

Pop off the bolt caps at the base of the toilet and unscrew the closet bolts (the nuts holding the toilet to the floor). If the bolts are rusted and won't turn, cut them with a hacksaw. Rock the toilet gently side to side to break the wax seal, then lift the toilet straight up and off the bolts. Toilets weigh 50-70 pounds — lift with your legs. Set the old toilet on a towel or garbage bag.

Examine the closet flange (the ring set into the floor around the drain). It should be firmly attached and sit flush with or slightly above the finished floor surface. If the flange is cracked or broken, install a repair ring (available at hardware stores for about $10). Insert new closet bolts into the flange slots and center them. Make sure the bolts stand straight up.

Place the new wax ring on the flange with the tapered (horn) side pointing down into the drain. Press it firmly into place. Alternatively, if you're using a wax-free ring (like Fluidmaster Better Than Wax), set it on the flange per the manufacturer's instructions. Remove the rag you stuffed in the drain.

Turn the new toilet bowl upside down or on its side to access the outlet horn. Lift the bowl and align the holes at the base with the closet bolts sticking up from the flange. Lower the bowl straight down onto the wax ring. Press down firmly and rock slightly to set the wax seal. Do not lift the bowl back up — once the wax compresses, lifting it breaks the seal and you'll need a new ring.

Place washers and nuts onto the closet bolts and tighten alternately (a few turns on each side) to draw the bowl down evenly. Don't overtighten — porcelain cracks under pressure. The bowl should be snug against the floor with no rocking. If the floor is uneven, slip plastic toilet shims under the base until it's stable, then trim the shims flush with a utility knife. Cut the bolts off with a hacksaw if they're too long, then snap on the bolt caps.

If your toilet has a separate tank, place the rubber gasket over the flush valve opening on the bottom of the tank. Set the tank onto the bowl, aligning the bolt holes. Insert the tank bolts with rubber washers and tighten alternately. Don't overtighten. Connect the water supply line to the fill valve at the bottom of the tank. Turn on the shut-off valve slowly and let the tank fill. Check every connection for leaks.

Run a bead of silicone caulk around the base of the toilet where it meets the floor, leaving a small gap at the back (so you can spot a future wax ring leak before it causes hidden damage). Smooth the caulk with a wet finger. Flush the toilet three or four times and check for leaks at the base, at the tank-to-bowl connection, and at the supply line. Verify the toilet fills and stops correctly.