How to Install a Commode Yourself: A Step-by-Step Guide

Quick answer (read this first)

• Turn off main water supply to the bathroom.
• Remove the old commode carefully.
• Thoroughly clean the toilet flange and surrounding area.
• Position new flange bolts and apply a new wax ring.
• Carefully set the new commode onto the flange.
• Secure the commode evenly to the floor.
• Reconnect water supply and check for leaks by flushing.

Safety first

• Always turn off the main water supply before starting work to prevent flooding.
• Wear protective gloves and eyewear to prevent cuts, maintain hygiene, and protect from splashes.
• Lift commodes with assistance or proper technique to avoid back strain and injury; they are heavy.
• Handle ceramic fixtures with extreme care; they are fragile and can break, causing sharp edges.
• Ensure good ventilation when working with sealants or adhesives to avoid inhaling fumes.
• Do not overtighten bolts, as this can crack the commode base.

Tools you may need

• Adjustable wrench
• Screwdriver (Phillips and flathead)
• Pliers
• Utility knife or putty knife
• New wax ring with flange bolts (often included)
• Level
• Bucket and old towels/rags
• Caulking gun and silicone sealant (optional)
• Sponge or cup for removing residual water

Step-by-step

Step 1

Locate and turn off your bathroom’s main water supply valve.

Step 2

Flush the old commode multiple times to empty the tank and bowl completely.

Step 3

Disconnect the water supply line from the commode’s fill valve.

Step 4

Remove any remaining water from the tank and bowl using a sponge or cup.

Step 5

Remove the decorative caps and nuts securing the old commode to the floor.

Step 6

Gently rock the old commode back and forth to break the wax seal.

Step 7

Carefully lift and remove the old commode from the flange, placing it on old towels or newspapers.

Step 8

Scrape off all remnants of the old wax ring from the toilet flange and surrounding floor.

Step 9

Thoroughly clean the flange area to ensure a smooth, debris-free surface for the new seal.

Step 10

Inspect the toilet flange for any cracks, corrosion, or damage; repair if necessary.

Step 11

Insert new flange bolts into the floor flange, ensuring they are upright and correctly aligned.

Step 12

Place the new wax ring (with or without horn, depending on your commode) onto the commode’s waste horn or directly onto the floor flange.

Step 13

Carefully lower the new commode straight down over the flange bolts, guiding it into position.

Step 14

Press down firmly and evenly on the commode to fully seat the wax ring.

Step 15

Place washers onto the flange bolts, then hand-tighten the nuts.

Step 16

Using an adjustable wrench, gradually tighten the nuts, alternating sides to apply even pressure.

Step 17

Tighten just until the commode is secure and doesn’t rock, being careful not to overtighten and crack the ceramic.

Step 18

Check the commode with a level to ensure it sits evenly on the floor; shim if necessary.

Step 19

Reconnect the water supply line to the new commode’s fill valve.

Step 20

Slowly turn the main water supply valve back on.

Step 21

Allow the commode tank to fill completely.

Step 22

Flush the commode several times to test functionality and check for leaks at all connections and the base.

Step 23

Replace the commode tank lid and seat.

Step 24

Install decorative caps over the flange bolts.

Step 25

If desired, apply a thin bead of silicone caulk around the commode base, leaving a small gap at the rear for ventilation.

Common mistakes

• Not turning off the water supply completely before starting, leading to spills or flooding.
• Reusing an old wax ring, which almost always results in leaks.
• Overtightening the flange bolts, causing the ceramic commode base to crack.
• Failing to properly clean the flange area, preventing a good, leak-proof seal.
• Not leveling the commode, leading to instability and potential leaks over time.
• Forgetting to check for leaks thoroughly after installation, which can lead to water damage.
• Improperly aligning the commode with the flange, damaging the wax ring and causing leaks.

When to call a professional

• If the existing toilet flange is broken, corroded, or damaged beyond a simple repair.
• You encounter persistent leaks that cannot be resolved with basic troubleshooting.
• There are issues with the main water supply valve that prevent it from turning off completely.
• You lack the appropriate tools or feel uncomfortable lifting and handling heavy ceramic fixtures.
• You suspect underlying plumbing issues, such as drain blockages or damaged pipes.
• If the commode repeatedly clogs or doesn’t flush properly even after installation.
• You encounter unexpected complications or structural damage during the removal or installation process.