How to Install a One-Piece Toilet
A one-piece toilet has the bowl and tank molded into a single unit, which makes it easier to clean but slightly different to install than a standard two-piece toilet. Here's the general process. (Still deciding between the two styles? See our one-piece vs. two-piece comparison.)
1. Shut Off Water and Remove the Old Toilet
Turn off the water supply valve behind the toilet, flush to empty the tank, and disconnect the supply line. Remove the tank bolts (if two-piece) or the base bolts, then lift the old toilet off the flange and set it aside.
2. Clean and Inspect the Flange
Scrape away the old wax ring completely and check that the closet flange (the pipe fitting in the floor) is in good condition and sits level with the finished floor. A cracked or poorly seated flange should be repaired before continuing.
3. Set the New Wax Ring
Place a new wax ring onto the flange, or onto the underside of the toilet base depending on the ring style you're using.
4. Lower the Toilet Into Place
Because a one-piece toilet is a single heavy unit, this step usually takes two people. Align the base bolts with the mounting holes and lower the toilet straight down onto the wax ring, pressing firmly to compress the seal.
5. Secure, Connect, and Test
Tighten the base nuts evenly (without overtightening, which can crack the porcelain), reconnect the water supply line, and turn the water back on. Flush several times and check around the base for any leaking.
What to Check Before You Buy
- Confirm your rough-in measurement (typically 12 inches from the wall to the flange center)
- One-piece toilets are heavier than two-piece models — plan for two people to carry and set it
- Check the bowl shape (round vs. elongated) fits your existing space
Browse our toilet collection to compare one-piece and two-piece options.