One-piece toilets, also known as all-in-one toilets, have become increasingly popular with homeowners in recent years. Compared to traditional two-piece models, they offer a sleeker, more modern look with fewer seams, which makes cleaning much easier. Because the tank and bowl are molded together, there’s no need to assemble separate parts, simplifying both installation and everyday use. For these reasons, many people choose a one-piece toilet when remodeling their bathrooms.
That said, while the design may look simple, the installation still requires careful attention—especially when it comes to moving the unit, positioning it correctly, and sealing it properly. If these steps are skipped or done incorrectly, you could end up with leaks or an unstable toilet.
In this guide, we’ll walk you through the entire installation process step by step: from the tools you’ll need and the prep work involved, to the final setup and finishing touches. Even if this is your first time, you’ll come away with a clear understanding of how to get the job done right.
Tools and Materials You’ll Need
Before you open the box, make sure you have all your tools ready. This will save you from unnecessary back-and-forth during the installation. Here’s a checklist to follow:
- Protective items: soft cloths or blankets (to protect the toilet and floor)
- Sealing materials: silicone or plumber’s tape, caulk gun, wax ring
- Measuring and marking: pencil or marker, tape measure, level
- Installation tools: adjustable wrench, locking pliers, basin wrench, screwdriver, socket extension
- Removal tools: putty knife, utility knife
- Included hardware (usually in the box): toilet body, toilet seat/lid, mounting bolts, plastic washers, expansion bolts, T-bolts, nuts, decorative caps
💡 Pro Tip: Lay out all the parts before you begin. Double-check that nothing is missing—it’s much easier to catch it now than halfway through the job.
Preparation Before Installation
- Shut off the water supply: If there’s no dedicated shutoff valve next to the toilet, close the home’s main valve.
- Drain the old toilet: Flush to empty the tank and bowl completely.
- Disconnect the supply line: Detach the hose from the old toilet.
- Remove the old toilet: Unscrew the nuts from the flange bolts and lift the toilet away.
- Clean the flange: Scrape away the old wax ring and sealant with a putty knife, then wipe clean.
- Block the drain temporarily: Use a rag or plug to cover the opening and keep sewer gases from escaping.
💡 Pro Tip: Old wax rings can be stubborn. Don’t rush it—use a utility knife to slice away the bulk before scraping.
Step-by-Step Installation of a One-Piece Toilet
- Install the floor bolts
Insert the bolts into the flange slots, twist 90° to lock them, and make sure they’re spaced about 6 inches apart and parallel to the wall.
- Mark your alignment
Draw light guide lines with a pencil or painter’s tape. This will help you lower the toilet into place straight, not crooked.
- Attach the wax ring
Lay the toilet gently on a blanket. Press the wax ring into the outlet (tapered side toward the toilet) and apply a thin bead of sealant around the base edge.
- Position the toilet
With two people lifting, carefully lower the toilet over the bolts and onto the flange, making sure it sits squarely on the wax ring.
- Secure the toilet
Tighten the nuts evenly from each side. Alternate turns to apply equal pressure. Don’t overtighten—too much force can crack the porcelain. Add decorative bolt caps.
- Check for leaks
Reconnect the water supply, turn it back on, and flush several times. Inspect all connections for drips or seepage.
- Seal the base
Run a clean bead of silicone caulk around the base of the toilet. This not only adds stability but also keeps out moisture and debris.
- Finish up
Install the seat and lid, and your toilet is ready for use.
Post-Installation Checks and Maintenance
Even if everything looks perfect at first, it’s smart to keep an eye on things for the next few days:
- Any water pooling around the base or at the supply connection?
- Does the toilet sit solidly without rocking?
- Is the caulk neat and sealed all the way around?
For long-term care, check the caulk and bolts every few years to make sure nothing has loosened or deteriorated.
💡 Extra Tip: If you run into misaligned drain openings or an uneven floor, don’t force the installation. Calling a plumber at that point can save you bigger headaches later.
Ending
Installing a one-piece toilet doesn’t necessarily require professional skills. With the right tools and a careful step-by-step approach, even beginners can get it done successfully. To make the process even easier, we’ve also included an installation video for visual guidance.
Please note: both this article and the accompanying video feature one-piece toilets sold by Giving Tree Home. While most steps will apply universally, different brands may have small variations. Always check your manufacturer’s instructions before beginning installation to ensure the best results.
