Replace a toilet

Every line shows the quantity to buy and how StudSheet got it: the spacing, the waste and the package size, so you can check it before the supply house or the quote.

In Canada (Toilet, 305 mm rough-in)

Set to Canada, the Sheet works the job out again for Ontario: metric sizes, bag sizes, the frost depth and the code notes. It doesn't just convert feet to meters. The first lines:

• 1 toilet, Toilet, basic: Rough-in 305 mm: wall to the center of the floor bolts. Chair height (about 432 mm to the seat) is easier to stand up from.
• 1 ring, Wax ring (or wax-free seal): One per toilet; never reuse the old ring — the horn guides the waste into the drain.
• 1 set, Closet bolts: New bolts; the old ones rarely come out clean.
• 1 line, Toilet supply line, braided: A new braided line every time: the old one is the leak waiting to happen.
• 1 tube, 100% silicone, color-matched: About 1.83 m around each base at a 6 mm bead, about 9.42 m a 300 mL tube. Many plumbers leave a gap at the back so a leak shows.

1. Measure the rough-in: from the finished wall (not the baseboard) to the center of the floor bolts — 12″ in most homes, 10″ or 14″ in some older ones.
2. Shut off the water at the valve, flush, sponge out the tank and bowl, and disconnect the supply line.
3. Take off the nuts, rock the toilet loose and set it on cardboard; stuff a rag in the drain and scrape off every bit of the old wax.
4. Check the flange: solid, screwed down, its top level with or just above the finished floor.
5. New bolts in the flange slots; the new wax ring on the toilet’s horn.
6. Set the toilet straight down over the bolts and press it down with your weight; shim it if it rocks.
7. Tighten the nuts a little at a time, side to side, just snug (porcelain cracks); cut the bolts and cap them.
8. Set the tank on the bowl as its instructions say, then connect the new supply line hand-tight + ¼ turn.
9. Turn the water on and check for leaks over a few flushes.
10. Caulk: run silicone around the base, leaving a gap at the back if you like so a leak shows.

Must-have tools first, then the ones that help and the ones to rent for the day.

Mistakes that cost a callback or a second trip

• Measuring from the baseboard: The rough-in is from the finished wall. Off by the baseboard and the new toilet won’t fit.
• Reusing the wax ring: A used ring never seals again. New ring every time the toilet comes up.
• Cranking the nuts: Porcelain cracks. Snug, side to side, and stop.
• Ignoring the flange height: After new tile the flange can end up below the floor: the ring can’t seal. Extender first.
• A rocking toilet: Rocking breaks the seal. Shim it before the nuts go tight.
• The old supply line: Old lines burst. A new braided line costs a few dollars.

What the calculator assumes

• Rough-in: 12″ unless you pick 10″ or 14″ (or measure).
• Supply line: 12″, 16″ for a 14″ rough-in; the stop about 6″ up the wall and 6–8″ left of center (typical).
• Silicone: about 6 ft around a base at a ¼″ bead.
• Paid work: many places license plumbers for fixture work too — check the rules where you work before you quote a swap.

The Sheet sets its code notes for the job's state or province. These are New Jersey's and Ontario's; the code reference has more. Always confirm with your building department.

• Room around the fixtures: Codes ask for about 15″ from the center of a toilet or sink to a wall or the next fixture, and 21″ clear in front (IRC R307.1; R327 in the 2024 IRC).
• The old toilet: Old toilets go out with bulk pickup or a dumpster — ask your town; some recycle the porcelain. Bag the old wax and drain the tank first.

What materials do I need to replace a toilet?

For the worked example, a toilet, 12″ rough-in, the Sheet counts 5 lines with waste included, starting with toilet, basic (1 toilet), wax ring (or wax-free seal) (1 ring), closet bolts (1 set), toilet supply line, braided (1 line). Each line's math is in the table above. Put in your own sizes in the toilet calculator and every line is counted again.

How long does it take to replace a toilet, and can I do it myself?

About 2 to 3 hours for the worked example, in 10 steps. StudSheet stamps it DIY OK: you can do this.

What tools do I need to replace a toilet?

14 in all. The must-haves start with tongue-and-groove pliers, screwdriver set, putty knife, 5-gal buckets (2), torpedo level, tape measure (25 ft). On the Sheet you mark each one as owned, to buy or to rent.

Stuck while you replace a toilet? Ask in the Toilets group of the StudSheet community with this Sheet attached. Homeowners who've done it and verified pros answer, and anyone can read it.

• Plumbing for contractors: run this takeoff at your own prices, send the estimate, and get it signed and the deposit paid.
• Plumbing rough-in (3 fixtures): For plumbers: supply and drain pipe by size, fittings, valves and vents for the fixtures you are adding.
• Water heater replacement (Gas water heater, 4 people): For plumbers: tank or tankless, venting, expansion tank, relief line, connections and the permit.
• Replace a bathroom vanity (30″ vanity): A vanity that fits the space and the pipes, its top and faucet, new supply lines, trap, shims and sealant — swapped in an afternoon.
• Replace a faucet (Kitchen faucet): A kitchen or bathroom faucet that fits your sink’s holes, new supply lines, the right sealant, and a leak check — or a cartridge for a drip.
• All 45 Sheets, across 16 trades.
• Code reference: frost depths, guard heights, stairs, retaining walls.