Tools and materials you'll need
- Adjustable wrench (8" minimum)
- Putty knife or paint scraper
- Bucket and old towels (for water cleanup)
- Wax ring (or wax-free urethane gasket — see notes below)
- Closet bolts (usually included with the toilet, but inspect them — replace if corroded)
- New supply line (3/8" to 7/8" toilet connector, braided stainless steel preferred)
- Bathroom-grade silicone caulk (optional — used to seal the toilet base to the floor)
- Level (for setting the toilet square)
- Helper to lift the new toilet — especially for one-piece models
Step 1 — Shut off water and drain the old toilet
Locate the shut-off valve on the wall behind or beside the toilet (usually a small chrome valve with a star-shaped knob). Turn it clockwise until firmly shut. Flush the toilet to drain the tank. Hold down the flush handle for 10–15 seconds to drain as much water as possible from the bowl trapway. Use a sponge or wet-dry vacuum to remove any remaining water from the tank and bowl.
Step 2 — Disconnect supply line and remove the old toilet
Loosen the nut connecting the supply line to the bottom of the tank (use the adjustable wrench). Some water will drip — have a bucket ready. Remove the supply line.
Locate the two closet bolts at the base of the toilet (often hidden under decorative caps). Remove the caps and loosen the nuts with the adjustable wrench. The bolts are threaded into the closet flange in the floor and shouldn't spin freely — if they do, hold the bolt head with pliers while loosening the nut.
With both bolts removed, gently rock the toilet side to side to break the wax ring seal. Lift the toilet straight up — be careful, it's heavy (50–120 lbs depending on type). Set it on old towels or out of the bathroom.
Step 3 — Clean the closet flange
The closet flange is the white or metal ring in the floor where the toilet bolts down. Use a putty knife to scrape off the old wax ring residue completely. Clean any debris from the drain opening. Inspect the flange:
- If the flange is intact and sitting flush with the floor surface: you're good to proceed.
- If the flange is broken, cracked, or sitting below the finished floor: stop. Repair the flange first, or call a plumber. A failed flange installation will leak.
- If the flange is sitting higher than the finished floor by more than 1/4 inch: also problematic. The toilet won't sit flush against the floor.
Step 4 — Install closet bolts and wax ring
Slide the new closet bolts into the slots in the flange so they're standing vertically. The bolt heads sit in the flange slots; the threaded ends point up.
Place the wax ring over the drain opening, centered on the flange. The wax ring is the seal between the toilet and the drain — it has to compress and form a watertight seal when the toilet is set. Some plumbers prefer urethane gaskets (Wax-Free Toilet Seal, Fluidmaster Better Than Wax) for easier alignment and reusability. Either works.
Step 5 — Set the new toilet
This is the step that benefits most from a helper. Lift the toilet over the flange, align the holes in the toilet base with the closet bolts sticking up, and lower the toilet straight down. Don't twist or rock the toilet during set — that breaks the wax ring seal. Set it straight down in one motion.
Once set, sit on the toilet briefly to compress the wax ring. This is normal and necessary for a watertight seal.
Step 6 — Tighten closet bolts
Place the washers and nuts on the closet bolts. Tighten the nuts evenly, alternating side to side (similar to tightening lug nuts on a car wheel). Don't over-tighten — porcelain cracks. The toilet should be firm against the floor with no rocking, but you should NOT need to crank hard on the wrench. If the toilet still rocks at moderate tightness, use plastic shims under the base to stabilize (cut off the excess shim with a utility knife).
Step 7 — Connect supply line and water
Connect the new supply line to the bottom of the tank (hand-tight, then 1/4 turn with the wrench — over-tightening cracks the porcelain at the fill valve nut). Connect the other end to the shut-off valve.
Slowly turn the shut-off valve counterclockwise to allow water to fill the tank. Watch for leaks at both connection points and at the base of the toilet.
Step 8 — Test flush and check for leaks
Once the tank fills, flush the toilet. Watch for water seepage around the base (indicates wax ring leak), around the supply line connection, or from the tank-to-bowl gasket (on two-piece toilets). Flush 3–5 times to confirm everything seals.
Optional: apply a thin bead of bathroom silicone caulk around the base of the toilet where it meets the floor. This prevents water from getting under the base and rotting the floor structure. Leave a small gap (1–2 inches) at the back to allow water to escape if the wax ring ever fails — that's your warning sign before the floor rots.
Most common DIY install mistakes
- Wrong rough-in — buying a 10-inch or 14-inch rough-in toilet for a 12-inch flange (or vice versa). Measure twice.
- Forgetting the wax ring — yes, this happens.
- Over-tightening the closet bolts — porcelain cracks. Snug, not cranked.
- Rocking the toilet during set — breaks the wax ring seal. Set it straight down.
- Not testing for leaks before assuming it's done — flush 5+ times and inspect for any seepage. A slow leak ruins floors over weeks.
Total time for an experienced DIYer: 60–90 minutes for a two-piece toilet, 90–120 minutes for a one-piece. For a first-time DIYer, double those estimates. If you're not confident with plumbing or the closet flange needs repair, hiring a plumber ($200–$400) is money well spent.