Renovation guides

How to replace a toilet

Draft guide written from standard practice, not yet reviewed by a licensed pro. Follow product labels where they differ.

Difficulty 3 of 5 · about half a day · careful

Photo of your room, the look you pick, then this guide with the materials counted for your room.

Step by step

1. Step 1 of 11

   Read the stop-gate, then look at the valve and the floor

   

   This job sets a new toilet on the same drain, in the same spot, on the same valve. Look at the shutoff valve behind the toilet: it should turn by hand. Press on the floor all around the base and look for dark stains, cracked tile, or a soft spot. Anything on the stop-gate list goes to a plumber or a flooring pro before this job.

2. Step 2 of 11

   Measure the rough-in and the supply line

   

   Measure from the finished wall behind the toilet, not the baseboard, to the center of one of the bolt caps at the base. That is your rough-in, usually 12 in, sometimes 10 or 14 in; buy a toilet made for it — the box and the spec sheet say which. Measure from the valve to where the tank's fill valve will be, for the supply line.

3. Step 3 of 11

   Water off at the toilet and prove it

   

   Close the shutoff valve behind the toilet gently, clockwise, until it stops. Flush and hold the lever down: the tank empties and should not refill. Wait a few minutes and look again: no water coming into the tank, no drip at the valve stem. If the valve will not close fully, weeps, or will not turn, stop here — a plumber replaces it before the toilet comes off. Find the home's main shutoff before you go on.

   Safe to start?

   • The shutoff valve closes fully: the tank stays empty and nothing drips at the valve stem
   • You know where the home's main water shutoff is
   • The new toilet is made for your rough-in, and a new seal, new bolts, and a new supply line are on hand
   • The floor around the toilet is firm, with no soft spot or dark stain
   • A helper is here to lift, and the way out of the bathroom is clear

4. Step 4 of 11

   Empty the tank and the bowl

   

   With the valve closed, flush and hold the lever down. Wearing gloves, sponge the last water out of the tank, then out of the bowl — a wet/dry vacuum is faster. A dry toilet is lighter and leaves no mess on the way out. If a fixtures-removal job in your plan already took the old toilet out, skip to step 6.

5. Step 5 of 11

   Disconnect the supply, unbolt, and lift the old toilet out

   

   Towel under the valve; undo the supply line at the tank, then at the valve. Pop the caps off the bolts at the base and undo the nuts; cut a seized bolt with the mini hacksaw rather than twisting the porcelain. Rock the bowl gently side to side to break the seal, then lift it straight up with your helper and set it on old towels or cardboard. Stuff a rag into the drain right away, with a corner hanging out, so no sewer gas comes up and nothing falls in.

6. Step 6 of 11

   Scrape the flange and look hard at it and the floor

   

   Scrape the old wax off the flange and the floor with the putty knife and bag it. Look at the flange: cracked, broken at the bolt slots, loose from the floor, or far below the finished floor is a stop — see the stop-gate. A flange a little below the finished floor takes a thicker seal or a flange extender kit made for that, per its package. Press the floor around the flange: soft or dark wood is a repair before the toilet goes back. In a home from before 1980, do not scrape or break old flooring or its adhesive around the flange — test first.

   Before the new toilet goes down

   • The flange is whole, tight to the floor, and its bolt slots are sound
   • The flange sits at or just above the finished floor — or you have the thicker seal or the extender kit made for a low one
   • The floor around the flange is firm and dry, with no soft or dark wood
   • Old flooring and adhesive around the flange were left alone, or the home is from 1980 or later, or they tested negative for asbestos

7. Step 7 of 11

   Set the new bolts and the new seal

   

   Slide the new closet bolts into the flange slots and hold them upright with their washers, lined up parallel to the wall. Fit the new wax ring or waxless seal the way its package says — on the flange or on the toilet's outlet. Pull the rag out of the drain just before the bowl goes down.

8. Step 8 of 11

   Lower the bowl straight down and bolt it evenly

   

   With your helper, lower the bowl straight down over the bolts in one motion, without sliding or twisting. Press down on the rim with your weight to seat the seal. If the bowl rocks, slip shims under it. Put on the washers and nuts and tighten them a few turns at a time, side to side, until the bowl is firm — then stop. Check it is level side to side and front to back. If you had to lift it again, use a new seal.

9. Step 9 of 11

   Set the tank and connect the new supply line

   

   Two-piece toilet: fit the tank gasket and the tank bolts the way the instructions say, and tighten the bolts a little at a time, side to side, until the tank sits level and firm on the bowl. Connect the new supply line to the fill valve and to the shutoff valve hand-tight, then give it the small extra turn its package says — no thread tape on compression fittings. Fit the seat.

10. Step 10 of 11

    Water on slowly and test

    

    Open the valve slowly. Let the tank fill and set the water level to the mark inside the tank, as the instructions say. Flush several times while you watch the supply nut, the tank bolts, and the base with a dry paper towel. Lay dry paper towels around the base and under the valve, and look again after an hour and the next day — a slow leak shows only with use.

11. Step 11 of 11

    Caulk the base — front and sides only

    

    Once the toilet has stayed dry for a day of use, run a thin bead of silicone around the front and the sides of the base where it meets the floor. Leave the back open, so a failed seal shows on the floor instead of soaking the subfloor. If an inspector requires the full base caulked, do what the inspector says.

    Quality check

    • The toilet does not rock in any direction; the bolts are snug and capped
    • No drip at the supply line, the valve, the tank bolts, or the base after a day of use
    • The tank fills to the mark, the flush is strong, and the fill valve shuts off
    • The shutoff valve still closes fully
    • The base is caulked at the front and sides and open at the back — or all around if your inspector requires it

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