How to Install a Toilet
Learn how to properly seat, seal, bolt down, and plumb a residential toilet to ensure a completely leak-free seal without cracking the porcelain.
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🧰 Required Tools & Equipment
- ✓ Adjustable wrench
- ✓ Torpedo level
- ✓ Tape measure
- ✓ Utility knife
- ✓ Bucket and sponge
- ✓ Screwdriver
📦 Materials & Supplies
- ✓ Toilet bowl and tank
- ✓ Wax ring with flange horn
- ✓ Brass closet bolts with nuts and plastic washers
- ✓ Braided stainless steel water supply line
- ✓ Plastic toilet shims
⚠️ Safety Checkpoints & Warnings
- • Shut off the main or local water supply valve completely and confirm line is depressurized before beginning.
- • Lift the toilet bowl using your legs and keep it close to your core to prevent lower back injury.
- • Never over-torque metal nuts against bare ceramic; porcelain will crack abruptly under excessive pressure.
📋 Step-by-Step Guide (6 Steps)
Prep Flange and Set Closet Bolts
Scrape away any old wax residue from the floor flange using a putty knife or rag. Slide the brass T-bolts into the flange collar channels parallel to the rear wall, spaced evenly to match the bowl base holes. Slide plastic retaining washers over the bolts down to the flange to hold them upright.
- • Clean, bare PVC or cast-iron flange surface free of old wax.
- • Two brass bolts standing perfectly vertical and equidistant from the finished back wall.
- • Leaving bolts loose so they fall over or twist sideways when dropping the heavy bowl.
Position Wax Ring
Unwrap the wax ring at room temperature. Center the ring directly over the floor flange collar with the tapered rubber horn facing downward into the drain pipe. Ensure the wax is sticky, pliable, and seated firmly without obstructing the bolt channels.
- • Wax ring centered symmetrically over the circular pipe opening with horn pointing down.
- • Attaching the wax ring to the bottom of the toilet instead of the flange, risking it falling off-center during placement.
Lower and Seat the Toilet Bowl
Straddle the floor flange and lift the toilet bowl by the rim. Align the holes in the bowl base with the vertical closet bolts and lower the bowl straight down without twisting. Press down firmly with body weight on the center of the bowl to compress the wax ring until the base meets the floor.
- • Closet bolts protruding cleanly through both mounting holes on the base.
- • Bowl base resting flat against the floor without rocking.
- • Wiggling, twisting, or lifting the bowl after making contact with the wax, which breaks the airtight seal.
Level and Secure the Bowl
Place a torpedo level across the rim front-to-back and side-to-side, sliding plastic shims under low spots if the floor is uneven. Slide the plastic bolt cap washer, metal washer, and nut onto each bolt. Alternate tightening each side incrementally with an adjustable wrench until snug, stopping the moment the bowl resists rocking.
- • Level bubble centered in both axes.
- • Bowl immovably firm with no rocking when pushed laterally.
- • Plastic shims trimmed flush with the outer porcelain edge.
- • Tightening one side down completely before touching the other, causing uneven stress.
Attach Tank to Bowl
Fit the large rubber spud gasket over the flush valve nut on the tank underside. Carefully lower the tank onto the back of the bowl, aligning the tank bolt holes with the bowl platform. Insert rubber-gasketed tank bolts through the inside of the tank and tighten the nuts underneath by alternating sides until the tank sits level and touches the bowl stabilizers.
- • Tank standing level and parallel to the back wall.
- • Tank porcelain stabilizers making firm contact with bowl rim pads without gaps.
- • Omitting the rubber washers inside the tank, leading to constant internal bolt leaks.
Connect Water Supply and Leak Test
Thread the flexible braided supply line by hand onto the threaded shank at the bottom of the fill valve, then tighten an extra quarter-turn with a wrench. Connect the other end to the shutoff valve and tighten securely. Slowly open the shutoff valve, let the tank fill, and inspect all connections, base bolts, and the floor perimeter with dry fingers or tissue paper for moisture.
- • Water fills the tank smoothly and shuts off automatically at the fill line.
- • Dry paper towel wiped along base, tank bolts, and water connections remains totally dry after 3 test flushes.
- • Cross-threading the plastic fill valve threads with the metal hose coupling.
Credit: inspired by an original tutorial by Home RenoVision DIY — watch the original on YouTube.
Don’t have everything?
- No Wax ring? Rubber or foam wax-free toilet gasket
- No Plastic toilet shims? Cut strips from a plastic gift card or vinyl floor scrap