How to Replace a Toilet: Step-by-Step Guide from a Professional Plumber

Replacing a toilet is one of the most common bathroom upgrades homeowners consider. Whether your toilet is leaking, cracked, outdated, or simply inefficient, installing a new one can improve comfort and reduce water waste.

At Nido Plumbing, our licensed plumbers replace toilets every day. While many homeowners choose professional installation, this guide walks you through how to replace a toilet step by step, explains what tools you’ll need, and highlights when it’s best to call a professional plumber.

Tools and Materials Needed to Replace a Toilet

Tools

• Adjustable wrench or 1/2" wrench

• Flathead screwdriver

• Utility knife

• Putty knife or scraper

• Bucket and towels

• Sponge or wet/dry vacuum

• Level

Materials

• New toilet (one-piece or two-piece)

• New wax ring or wax-free toilet seal

• New closet bolts and hardware

• New toilet supply line

• Plastic toilet shims

• Bathroom-grade caulk (optional)

Step-by-Step Instructions: How to Replace a Toilet

Step 1: Turn Off the Water Supply

Locate the toilet shutoff valve behind the toilet and turn it clockwise until fully closed. Flush the toilet to empty the tank.

Plumber Tip: If the valve won’t shut off completely, turn off your home’s main water supply.

Step 2: Drain the Toilet Tank and Bowl

Hold the flush handle down to remove most of the water. Use a sponge or wet/dry vacuum to remove any remaining water from the tank and bowl. Place towels around the base to catch spills.

Step 3: Disconnect the Water Supply Line

Place a bucket under the connection and disconnect the supply line from the toilet tank. Replacing the supply line is highly recommended to prevent future leaks.

Step 4: Remove the Toilet Tank (Two-Piece Toilets Only)

For two-piece toilets:

1. Remove tank bolts from inside the tank

2. Loosen the nuts underneath

3. Lift the tank straight up and set it aside

Step 5: Remove the Toilet Bowl

Remove the bolt caps at the base, loosen the nuts, and gently rock the toilet to break the wax seal. Lift the toilet straight up and move it aside.

⚠️ Toilets are heavy—get help if needed.

Step 6: Plug the Drain Opening

Place a rag into the drain opening to block sewer gas and prevent debris from falling in.

Step 7: Remove the Old Wax Ring and Inspect the Flange

Scrape away all old wax and inspect the toilet flange. The flange should be secure, level, and undamaged.

Important: A broken or low flange is a leading cause of toilet leaks and often requires professional repair.

Step 8: Install New Closet Bolts

Install new closet bolts into the flange slots and position them evenly across from each other.

Step 9: Install the New Wax Ring or Seal

Attach the wax ring to the toilet outlet or place it directly on the flange, following manufacturer instructions.

Never reuse a wax ring.

Step 10: Set the New Toilet Bowl

Carefully lower the toilet onto the flange, aligning the bolts. Press down firmly to create a proper seal.

🚫 Do not lift the toilet once the wax is compressed.

Step 11: Secure and Level the Toilet

Tighten the nuts evenly—do not overtighten. Use plastic shims to level the toilet and eliminate rocking.

Step 12: Reinstall the Tank (If Applicable)

Install the tank gasket, set the tank on the bowl, and tighten bolts evenly until secure.

Step 13: Reconnect the Water Supply

Connect the new supply line to the shutoff valve and fill valve. Hand-tighten, then snug slightly with a wrench.

Step 14: Turn the Water Back On and Test

Turn the water on and allow the tank to fill. Flush multiple times and inspect for leaks around:

• Supply line connections

• Tank bolts and gasket

• Base of the toilet

Step 15: Caulk the Base (Optional)

Apply caulk around the front and sides of the toilet base, leaving a small gap at the back to allow leaks to be visible.

Common Toilet Installation Mistakes to Avoid

• Reusing an old wax ring

• Ignoring flange damage

• Overtightening bolts

• Skipping leak testing

• Leaving the toilet unlevel

Should You Replace a Toilet Yourself or Hire a Plumber?

While many homeowners can replace a toilet, problems such as:

• Damaged toilet flanges

• Leaks after installation

• Uneven floors

• Old or corroded plumbing connections

are best handled by a licensed professional plumber to prevent water damage and costly repairs.

Call Nido Plumbing for Professional Toilet Installation

If you’d rather skip the hassle—or want peace of mind knowing the job is done right—Nido Plumbing is here to help. Our experienced plumbers provide fast, reliable toilet installation and repair services.

✅ Why Choose Nido Plumbing?

• Licensed & insured plumbers

• Upfront pricing

• Clean, professional workmanship

• Reliable residential plumbing service

📞 Call Nido Plumbing today to schedule your toilet replacement💻 Request service online for fast, professional plumbing help

A properly installed toilet protects your home from leaks and water damage. Trust Nido Plumbing to get it done right the first time.