Can I replace a toilet myself?

Yes — for the great majority of homes this is a genuine DIY job needing no permit, because you are reconnecting to an existing flange and drain, not altering the plumbing in the wall or floor. The two real challenges are the weight (a one-piece toilet can top 100 pounds, so get a helper) and setting the wax ring cleanly in a single try. Where it stops being DIY is a damaged or rotted flange, a soft floor around the base, or moving the toilet's location — those bring in a plumber and sometimes a permit.

How do I know if I need a new wax ring or a whole new toilet?

If the china is sound and it flushes well, a leak at the base is almost always just the wax ring, which is a $5 part and a 45-minute job — no need to replace the toilet. Replace the whole toilet when the bowl or tank is cracked, when it clogs constantly despite a clear trap, when it rocks because the base is chipped, or when you simply want a taller comfort-height or higher-efficiency model. A hairline crack in the tank is not repairable and is a genuine reason to replace.

What size wax ring should I use?

Match it to your flange and toilet. A standard wax ring fits a 3-inch or 4-inch waste line and most toilets. Use a wax ring with a plastic funnel (horn) if your flange sits at or below floor level, as the horn helps direct waste into the pipe and improves the seal. If the flange sits low because of a thick new floor, stack a second plain wax ring or use an extra-thick ring rather than hoping one ring bridges the gap — a stretched wax seal is the classic slow leak.

How tight should the toilet bolts be?

Snug, alternating side to side, and stop the moment the toilet stops rocking — do not keep cranking. The tank and base are vitreous china and will crack under too much bolt torque, usually days later. Hand-tighten the nuts, then use a wrench to take them just past finger-tight, alternating left and right a little at a time so the bowl settles evenly onto the wax ring. If the toilet still rocks slightly, shim it with plastic toilet shims rather than over-tightening the bolts.

Do I need to caulk around the base of a new toilet?

Most plumbing codes recommend it, and many require it, because caulk keeps mop water and spills from getting under the toilet and hiding a leak or growing mildew. Caulk around the front and sides but leave a small gap at the very back unsealed, so that if the wax ring ever fails, water escapes and warns you rather than pooling invisibly under the base and rotting the subfloor. Use a bathroom-grade silicone or tub-and-tile caulk.

How to Replace a Toilet: Full Step-by-Step DIY Guide

Written & researched by Priya Anand DIY & Tools Editor

Updated August 2026

Golden-hour view of a person's hands tightening a fitting under a kitchen sink with a wrench

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Replacing a toilet is a real DIY project — about 2 hours, roughly $100 to $400 for the toilet, no permit in most jurisdictions, but definitely a two-person lift. You shut off and drain the old one, unbolt and remove it, scrape the flange clean, set a fresh wax ring, drop the new bowl straight down, snug the bolts and reconnect the water. The two ways it goes wrong are a botched wax-ring seal and over-tightened bolts that crack the china. Call a plumber if the flange is broken or the floor beneath it is soft — that is repair work beyond a straight swap.

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How to Change a Toilet — Ask This Old House

Tools and materials

New toilet (know your rough-in — the distance from the wall to the center of the floor bolts, usually 12 inches), a new wax ring (buy two), and new closet bolts.
Adjustable wrench, a hacksaw or bolt cutters, a putty knife, a sponge and bucket, rags, and shims.
A new braided supply line and bathroom-grade silicone caulk.
Basic hand tools from a plumbing tool kit, plus a helper for the lift.

Over-the-shoulder view of a person's hands tightening a fitting under a kitchen sink with a wrench, in warm late-afternoon light

Step 1: Shut off, drain, and remove the old toilet

Close the shutoff valve behind the toilet and flush, holding the handle to drain as much as possible. Sponge the remaining water out of the tank and bowl — a wet-dry vac is faster. Disconnect the supply line. Pry off the bolt caps at the base and remove the two nuts; if a bolt spins, cut it with a hacksaw. Rock the toilet gently to break the wax seal, then lift it straight up (with your helper) and set it on a towel or cardboard. Stuff a rag into the open drain pipe to block sewer gas.

Step 2: Scrape the flange and check its condition

Remove the rag briefly and scrape all the old wax off the flange with a putty knife until the metal or plastic ring is clean. Inspect the flange now — it should sit on top of the finished floor and be intact. If it is cracked, badly corroded, or below the floor level, stop and address it (a repair flange or a plumber) before going further; a compromised flange is the most common reason a new toilet leaks. Set new closet bolts into the flange slots, pointing up, and position them evenly on each side.

Close-up detail of the material being worked in a diy plumbing project, in warm late-afternoon light

Step 3: Set the wax ring

Press a new wax ring onto the underside of the toilet's outlet horn, or onto the flange — either works, but on the horn gives you a clear view of the alignment. Use a funnel-style ring if the flange is at or below floor level. You get one attempt: once the toilet touches the wax and you have pressed down, lifting it to re-aim ruins the seal and you must start with a fresh ring. So aim carefully before you commit.

Step 4: Set the new toilet

Lift the bowl over the drain, line the two bolt holes up with the closet bolts, and lower it straight down without twisting. Once it is seated on the bolts, press down firmly with your body weight and a slight rock to compress the wax ring evenly. Slip on the washers and nuts and tighten them alternately, a little each side, until the toilet stops moving — then stop. Over-tightening cracks the base. Shim any remaining wobble. Snap on the bolt caps (cut the bolts to length first if needed).

Wide view of a person's hands tightening a fitting under a kitchen sink with a wrench, in warm evening lamplight

Step 5: Reconnect, test, and caulk

If it is a two-piece toilet, bolt the tank onto the bowl now, tightening the tank bolts evenly and just until snug. Connect the supply line to the fill valve and the shutoff — hand-tight plus a quarter turn. Open the valve, let the tank fill, and flush several times while you watch the base and the tank-to-bowl connection for any water. Check again after a full day. Finally, run a bead of silicone caulk around the base, leaving a gap at the back so a future leak has somewhere to show itself.

Common mistakes

Re-aiming after the wax ring touches down. Ruins the seal. Aim once, commit once.
Over-tightening the closet or tank bolts and cracking the china — often days later.
Ignoring a low or damaged flange and hoping the wax bridges the gap.
Sealing the caulk all the way around, hiding a future leak that then rots the subfloor.

When to call a plumber

Call a pro if the closet flange is broken or sits below a newly raised floor, if the subfloor around the toilet feels spongy (water damage that needs repair before a toilet goes back), if you are relocating the toilet to a new spot, or if the shutoff valve is seized. Moving or adding a drain line is code-regulated work that typically needs a permit and inspection; a straight replacement onto a sound existing flange does not. If cost is your deciding factor, see how much it costs to replace a toilet.

How to Replace a Toilet