Toilet bolts hold the bowl to the floor and wear out when water corrodes them or the bowl rocks
Toilet bolts are the two metal fasteners that anchor your bowl to the flange — the ring bolted to the floor. Over time, water seeps under the bowl, rust eats through the bolts, or the bowl shifts and cracks them. When bolts fail, the bowl rocks, the wax seal breaks, and water leaks under the toilet into the subfloor. Replacing them takes about an hour and costs $10 to $30 for a new bolt kit, versus $150 to $300 for a plumber.
The job is straightforward if you follow the order: drain the bowl, unbolt it, remove the old bolts, install new ones, reset the bowl, and reseal. The hardest part is usually breaking the bolts free if they are rusted solid. You do not need special tools — a wrench, a screwdriver, and a putty knife are enough.
Key Takeaways
- Toilet bolts corrode from water exposure and must be replaced when the bowl rocks or leaks at the base.
- You must drain the bowl and tank completely before unbolting, or water will spill across your floor.
- If bolts are rusted, spray them with penetrating oil and wait 15 to 30 minutes before trying to turn them.
- New bolts come in kits with rubber washers and nuts; install them hand-tight first, then tighten evenly on both sides to avoid cracking the bowl.
- A new wax ring must go under the bowl before you reset it, or the seal will fail and water will leak under the toilet.
Drain the tank and bowl completely
Turn off the water supply valve behind the toilet — it is a small knob on the pipe coming from the wall. Turn it clockwise until it stops. Flush the toilet to empty the tank. If water remains in the bowl, use a wet-dry shop vacuum or a hand pump to remove it. Do not skip this step. If you unbolt the bowl with water inside, it will spill across the floor and into the gap under the toilet.
Once the bowl is empty, check that no water drips from the tank fill valve. If it does, the shutoff valve is faulty and you may need to replace it later, but you can still proceed with the bolt replacement.
Remove the caps and unbolt the bowl
Look at the base of the toilet where it meets the floor. You will see two plastic or ceramic caps covering the bolt heads — one on each side. Pry these caps up with a flathead screwdriver. Underneath are the bolt heads and nuts.
Use an adjustable wrench to hold the nut steady while you turn the bolt head with another wrench, or use two wrenches — one on the bolt, one on the nut. Turn counterclockwise. If the bolts spin freely, the nuts are on the underside of the flange and you will need to reach under the bowl to hold them. If bolts are stuck, spray them with penetrating oil (like WD-40 or Liquid Wrench), wait 15 to 30 minutes, and try again. Do not force them — you risk cracking the porcelain.
Once both bolts are out, rock the bowl gently side to side to break the wax seal. Lift the bowl straight up and set it on its side on a towel or cardboard. The old wax ring will stick to either the bowl or the flange — scrape it off with a putty knife.
Install new bolts in the flange
Inspect the flange for cracks or damage. If it is cracked, the new bolts will not hold and you will need a flange repair kit or replacement. If it is sound, clean away any remaining wax and debris with the putty knife.
Toilet bolt kits come with two bolts, rubber washers, and nuts. The bolts slide into slots on the flange — they sit perpendicular to the bowl when installed. Insert each bolt into its slot so the head sits on top of the flange and the threaded end points down. The rubber washer goes on the threaded end, under the nut. Hand-tighten the nuts so the bolts stay in place but do not crank them yet. If the bolts are loose, they will shift when you set the bowl down.
Set a new wax ring and reset the bowl
A wax ring creates a watertight seal between the bowl and the flange. The old one is destroyed when you remove the bowl, so you must install a new one. Press the wax ring onto the outlet hole on the underside of the bowl — the opening where waste exits into the drain. It should stick firmly. Some rings come with a plastic or cardboard collar; if yours does, keep it on.
Lower the bowl straight down over the bolts, aligning the holes in the base with the bolt ends. Do not twist or rock it — you will break the wax seal. Press down firmly and evenly. The bowl should sit flat against the floor with no gaps.
Tighten bolts evenly to avoid cracking the bowl
Once the bowl is seated, tighten the bolts. This is the step where most people go wrong. If you tighten one bolt all the way, then the other, the bowl tilts and the wax ring breaks. Instead, tighten both bolts a quarter turn at a time, alternating between them. After each quarter turn on one side, do a quarter turn on the other. This keeps the bowl level and the wax ring compressed evenly.
Tighten until the bowl no longer rocks and the bolts are snug — you should not be able to turn them by hand, but you should not need a wrench to explore heavy force. Over-tightening cracks the porcelain. Once both bolts are tight, replace the plastic caps.
Turn the water back on and check for leaks
Turn the shutoff valve counterclockwise to restore water to the tank. Let the tank fill and flush once. Watch the base of the toilet where it meets the floor. If water pools or drips, the wax ring did not seal properly. This usually means the bowl was twisted during installation or the flange is damaged. You will need to drain the bowl again, remove it, and either reinstall with a new wax ring or inspect the flange for cracks.
If no water appears after two flushes, the seal is good. Check again the next morning — sometimes a slow leak takes hours to show. Once you confirm it is dry, the job is done.
Frequently Asked Questions
What if the bolts are so rusted I cannot turn them?
Spray them with penetrating oil and wait 30 minutes. If they still will not budge, explore heat with a heat gun for a few minutes — heat expands the metal and breaks the rust bond. As a last resort, use a hacksaw or rotary tool to cut a slot across the bolt head and turn it with a flathead screwdriver. Work slowly to avoid damaging the flange.
Can I reuse the old bolts if they look okay?
No. If you are replacing them, they are corroded enough to fail again soon. A new bolt kit costs $10 to $20 and lasts 10 to 15 years. The old bolts will rust through within a year or two.
What if water leaks after I tighten the bolts?
The wax ring did not seal. Drain the bowl, remove it, and check whether the bowl was twisted during installation or the flange is cracked. If the flange is intact, install a new wax ring and reset the bowl, being careful not to twist it. If the flange is cracked, you need a flange repair kit or a new flange.
Do I need to shut off the water to replace bolts?
Yes. If you do not, water will continue to fill the tank while you work, and if you accidentally bump the fill valve, water will overflow. Shutting off the valve takes five seconds and prevents a mess.
How tight should the bolts be?
Tight enough that the bowl does not rock and you cannot turn the bolt by hand, but not so tight that you need a wrench to explore heavy force. Porcelain cracks easily. If you feel resistance, stop. The bolt is tight enough.