Install Toilet
Set a new wax ring, position the toilet over the flange, bolt down securely, and test for leaks. Proper installation prevents water damage and odor issues.
Quick Summary
1-2 hours
$150-$600
Medium
Wrench, level, putty knife
Before You Start
Installing a toilet is straightforward, but the wax ring seal is unforgiving. Once you set the toilet, you can't lift it to check - that breaks the seal. Measure twice, set once.
What You'll Need
- • New toilet (bowl and tank)
- • Wax ring or wax-free seal
- • New closet bolts
- • Flexible supply line (braided stainless)
- • Toilet shims (if floor is uneven)
- • Adjustable wrench
- • Level
- • Putty knife
- • Hacksaw (for trimming bolts)
Check Your Flange
- • Flange should be level with or slightly above floor
- • If tile raised floor height, use flange extender
- • Flange should be securely attached to floor
- • Check for cracks or damage - replace if broken
- • Clean thoroughly - remove all old wax
Installation Steps
Prepare the Toilet Flange
Scrape off all old wax from the flange with a putty knife. Wipe clean with rags. Inspect the flange for cracks - a broken flange must be replaced or you'll have leaks. Ensure the flange is securely screwed to the floor or subfloor.
Install New Closet Bolts
Insert new closet bolts (sometimes called johnny bolts) into the flange slots. Position them parallel to the wall behind the toilet, equidistant from center. Slide on the bolt caps to keep them upright while you position the toilet.
Set the Wax Ring
Choose your method: Place the wax ring on the flange with the tapered (narrow) end pointing up, OR place it on the toilet horn (bottom outlet). Don't do both. If the room is cold, warm the wax slightly with your hands - this helps it compress and seal better.
Position the Toilet
This is the critical step. Lift the toilet bowl carefully (they're heavy - 40-60 lbs). Position it directly over the bolts, aligning the bolt holes. Lower straight down - don't tilt or shift. Once it touches the wax ring, press down firmly with a gentle rocking motion to compress the wax.
Bolt Down the Toilet
Slide washers over the bolts, then thread on the nuts. Hand-tighten first. Use a wrench to tighten evenly, alternating between bolts. Tighten until the toilet doesn't rock, but DON'T over-tighten or you'll crack the porcelain base. Gentle pressure is key.
Trim Bolts and Add Caps
Use a hacksaw to cut the closet bolts flush with the top of the nuts. Cut carefully to avoid scratching the porcelain. Snap on the decorative bolt caps. These protect the threads and look cleaner than exposed bolt ends.
Attach the Tank
If your toilet is two-piece, place the rubber tank-to-bowl gasket on the bowl opening. Lower the tank onto the bowl, aligning the mounting holes. Insert tank bolts with washers, hand-tighten nuts from below. Use a screwdriver to hold bolt heads while tightening nuts. Alternate sides, snug but not over-tight.
Connect Water Supply
Connect a flexible braided stainless steel supply line from the shutoff valve to the toilet fill valve (bottom of tank). Hand-tighten connections, then snug with wrench 1/4 turn. Turn on the shutoff valve slowly and let the tank fill. Check for leaks at both connections.
Test Thoroughly
Let the tank fill completely. Flush 3-5 times. After each flush, carefully check around the base for any water seepage. Check the supply line connection and tank bolts for leaks. Use a flashlight and look closely - even small leaks will cause floor damage over time.
Caulk Around the Base
Apply a bead of clear or white 100% silicone caulk around the toilet base where it meets the floor. Caulk the front and sides completely, but leave a small gap (1-2 inches) at the back. This gap allows water to escape if the wax ring ever fails, alerting you to a leak rather than rotting your floor silently.
Wax Ring vs. Wax-Free Seal
Traditional Wax Ring
Pros:
- • Proven technology - used for 100+ years
- • Very inexpensive ($3-8)
- • Creates excellent seal when compressed
- • Works in any temperature
Cons:
- • Messy to work with
- • Single-use only - can't reposition
- • Can harden over time in very hot attics
Best for: Most standard installations, permanent placement
Wax-Free Seal (Rubber)
Pros:
- • Reusable if toilet needs to be removed
- • Easier to position - not sticky
- • Works in extreme temperatures
- • Less messy to install
Cons:
- • More expensive ($10-15)
- • Requires very precise flange height
- • Newer technology - less proven long-term
Best for: Toilets that may need removal, extreme climates
Recommendation: Both work well when installed correctly. Use a standard wax ring for most permanent installations - it's proven and reliable. Use wax-free if you anticipate needing to remove the toilet soon (for tile work, repairs, etc.) or if you live in extreme climates where wax can harden or soften excessively.
Common Mistakes to Avoid
Lifting the Toilet After Setting
Once the toilet touches the wax ring, lifting it breaks the seal. You must start over with a new wax ring. Take time to align the bolt holes perfectly before lowering. Use a helper if needed - it's worth it to get positioning right the first time.
Over-Tightening Bolts
Porcelain cracks easily under uneven pressure. Tighten closet bolts and tank bolts just until snug - no more. If the toilet rocks, use shims to level it rather than cranking down the bolts. A cracked toilet base or tank is not repairable.
Ignoring Flange Height
If the flange is below floor level (common after adding tile), the wax ring can't compress properly and will leak. Use a flange extender to raise it. If the flange is broken, replace it before installing the toilet. These issues won't fix themselves.
Skipping the Level Check
An unlevel toilet rocks, stresses the wax seal, and eventually leaks. Use a level to check side-to-side and front-to-back. Shim as needed. A rocking toilet is a ticking time bomb for floor damage.
Not Testing Thoroughly
Flush multiple times and check carefully for leaks at the base. Don't just glance - get down on the floor with a flashlight and look closely. Small leaks can go unnoticed for months while rotting your subfloor. Test now, not later.
Frequently Asked Questions
Should I use a wax ring or wax-free toilet seal?
Traditional wax rings are reliable and inexpensive ($3-8) but messy and single-use. Wax-free seals (like Fluidmaster Better Than Wax) cost more ($10-15) but are reusable if you need to remove the toilet, don't harden in cold temperatures, and are easier to position. Both work well when installed correctly. For most installations, wax rings are perfectly adequate. Use wax-free for toilets that may need removal soon.
How do I know if the toilet flange is the right height?
The toilet flange should be flush with or up to 1/4 inch above the finished floor. If it's below the floor (common after adding tile), the wax ring won't seal properly and will leak. Use a toilet flange extender to raise it to the correct height. If the flange is more than 1/4 inch above the floor, use an extra-thick wax ring or two regular rings stacked.
How tight should I tighten the toilet bolts?
Tighten closet bolts until snug but not over-tight. The toilet should not rock, but you shouldn't crank down hard. Over-tightening cracks the porcelain base. Tighten evenly, alternating between bolts. If the toilet rocks after moderate tightening, use toilet shims rather than forcing it level with bolt pressure.
What if my toilet rocks after installation?
A rocking toilet means the floor is uneven or the toilet base isn't perfectly flat. Use plastic toilet shims to level it. Insert shims at low points around the base, cut flush with a utility knife, then caulk around the base. Never over-tighten bolts to force a rocking toilet down - this cracks the base and doesn't fix the seal.
Should I caulk around the base of the toilet?
Yes, caulk around most of the toilet base, but leave a small gap at the back. This meets code in many areas, prevents water and odors from getting under the toilet, and makes cleaning easier. The gap at the back allows water to escape if the wax ring fails, alerting you to a leak. Use clear or white 100% silicone caulk.