Installing a new toilet can seem like a daunting task, but with the right preparation and tools, installing a Kohler Highline toilet is actually quite straightforward. The Kohler Highline is a popular two-piece toilet known for its elegant curves and efficiency. With just a few basic plumbing skills and tools, you can have your new Kohler Highline toilet installed and functioning in no time.


A Kohler Highline toilet is a high-quality and reliable choice for a bathroom upgrade or remodel. Kohler is a leading plumbing fixtures brand that has been in business since 1873. The Kohler Highline toilet line offers a range of affordable, stylish, and well-performing toilets.

The two-piece Kohler Highline toilet features a classic elongated bowl design and is available in a range of heights from comfort height to standard height. It comes in a variety of colors like white, biscuit, almond, and black. Key features include:

  • Elongated bowl offers added room and comfort
  • Available in comfort height or standard height
  • Powerful flush uses 1.28 or 1.6 gallons per flush
  • ADA compliant models meet accessibility standards
  • Easy to clean vitreous china construction
  • Matching Kohler Highline tank included
  • 12 inch rough-in fits most existing installations
  • WaterSense certified high-efficiency models available

Installing a Kohler Highline toilet involves removing the old toilet, preparing the floor flange, installing the new toilet, and connecting the water supply. With some basic DIY skills and tools, you can install a Highline toilet in around 2-4 hours.

We’ll walk through the complete step-by-step process for how to install a Kohler Highline toilet below. Follow along to learn how to safely and properly install your new Kohler Highline toilet.

Gather Tools and Materials

Installing a new toilet requires gathering a few key tools and materials ahead of time. Here’s what you’ll need to have on hand:


  • Adjustable wrench
  • Channel lock pliers
  • Hacksaw (for cutting plastic bolts)
  • Crescent wrench
  • Tape measure
  • Screwdriver
  • Wax ring
  • Shop vacuum
  • Safety glasses
  • Gloves


  • New Kohler Highline toilet
  • Toilet seat bolts
  • Flange bolts/screws
  • Silicone caulk and caulk gun
  • Closet flange spacer (if needed)
  • Closet bolts for toilet
  • Supply valve and riser (if needed)
  • Teflon tape
  • Rags
  • Bucket
  • Wax ring/wax-free ring
  • Flexible water supply line

Shut Off Water Supply

Before removing your existing toilet, you’ll need to shut off the water supply. This prevents water from continuing to flow once the toilet is disconnected.

Locate the water shut off valve for the toilet. It’s usually on the wall behind the toilet or beside the tank. Turn it clockwise until it’s fully closed and no water continues flowing to the toilet.

Flush the toilet one last time to empty the tank and bowl as much as possible. Use a sponge to soak up any remaining water in the tank or bowl.

Disconnect and Remove Old Toilet

With the water supply off, you can disconnect and remove the old toilet.

Step 1: Disconnect Water Line

The first step is disconnecting the flexible water supply line from the toilet tank. Place a bucket under the end of the water line. Use tongue and groove pliers to unlock the coupling nut connecting the line to the tank fill valve. Allow the line to drain into the bucket, then disconnect it.

Step 2: Remove Tank Bolts

The tank is connected to the bowl with two tank bolts on either side. Use a screwdriver to loosen the nuts on the tank bolts. Carefully lift the tank and set it aside.

Step 3: Unbolt Toilet Bowl

With the tank removed, you can now access the bolts holding the bowl to the flange. Use a wrench to loosen and remove the nuts from the toilet bowl bolts. Set them aside to reuse or replace later.

Step 4: Remove Toilet Bowl

Lift the toilet bowl directly up to detach it from the flange in the floor. The old wax ring seal should release as you lift. Set the old toilet aside, being careful not to crack the bowl.

Step 5. Clean Flange

Use a shop vacuum to remove any remaining water or debris around the floor flange. Remove old wax with a plastic putty knife or rag. Thoroughly clean the exposed flange in preparation for the new toilet.

Install New Toilet on Flange

Once the old toilet is removed, you can install the new Kohler Highline on the existing flange.

Step 1: Inspect Flange Height

Check that the floor flange height is correct for your toilet model. The flange should be 1/4″ above the floor. If it is even with or below floor level, you may need to raise it up with a flange spacer before installing the new toilet.

Step 2: Install Wax Ring

Take the new wax ring and press it evenly onto the floor flange, centered with the bolts. The ring should form a secure seal between the flange and toilet.

TIP: For mess-free installation, opt for a wax-free gasket instead.

Step 3: Lower Toilet in Place

Carefully lift and position the new Kohler Highline toilet centered over the flange. Slowly lower it straight down onto the wax ring seal. The toilet should sit flat and stable on the floor.

Step 4: Insert Flange Bolts

From inside the empty toilet bowl, insert the provided bolts into the slotted holes on either side. The ends will protrude up through the base.

Step 5: Hand Tighten Nuts

Place a washer and nut onto the protruding ends of each flange bolt. Hand tighten them just enough to hold the toilet in place temporarily.

Connect Toilet Tank

With the bowl in place on the flange, you can reconnect the toilet tank.

Step 1: Install Toilet Tank

Lower the tank onto the bowl so the bolt holes are aligned. Hand tighten the nuts onto the tank bolts just enough to hold the tank in position.

Step 2: Connect Water Line

Attach the new flexible supply line to the tank fill valve. Tighten the coupling nut with pliers. Keep the shutoff valve closed for now.

Step 3: Secure Tank

Use a wrench to tighten the nuts on the tank bolts alternately and evenly. Do not overtighten. The tank should be snug against the bowl.

Step 4: Install Toilet Seat

Place the toilet seat onto the bowl, inserting the provided bolt posts through the holes. Tighten on the provided nuts and washers to secure the seat in place.

Complete Installation

With the toilet tank and bowl interconnected, complete the installation with a water supply connection and final adjustments.

Step 1: Open Water Supply

Turn on the water shut off valve to allow water to flow to the new toilet. Check for any leaks at the tank fill valve or connections. Tighten as needed to stop leaks.

Step 2: Flush Toilet

Flush the toilet several times to clear any dust or debris and ensure it is functioning properly. Check for a clean and effective flush.

Step 3: Secure Bowl to Flange

Use a wrench to evenly tighten down the nuts on the bowl flange bolts. Alternate sides as you tighten. The bowl should be completely snug to the floor.

Step 4: Apply Caulk

Run a smooth bead of silicone caulk around the toilet base where it meets the floor. This provides an additional seal against water leaks.

Step 5: Allow Caulk to Dry

Let the caulk fully cure for at least 6-12 hours before using the toilet. This ensures the strongest bond and seal.

And that’s it – your new Kohler Highline toilet is installed! Just give the bowl a quick clean and you’re ready to put it to use.

Troubleshooting Common Kohler Highline Toilet Installation Problems

While installing a new Kohler Highline toilet is generally straightforward, a few issues can come up. Here are some common installation problems and how to fix them:

Problem: The toilet rocks or wobbles when sitting on the floor.

Solution: The wax ring seal may be uneven or the floor flange height is incorrect. Try adding a flange extension spacer. Then re-seat the bowl on a new wax ring. Tighten down the bowl bolts evenly to stabilize.

Problem: The toilet bowl or tank is leaking from connections.

Solution: Check that all gaskets and washers are in place. Tighten nuts at tank bolts and supply line as needed. Make sure the coupling nut is tight.

Problem: Toilet won’t flush or flushes slowly.

Solution: Make sure the water supply is fully on. The fill valve chain may need adjusting to allow the flush valve to open fully. Clear any obstructions in the bowl or drain pipe.

Problem: Toilet keeps running constantly.

Solution: The flapper seal may need replacing if worn out. Adjust the chain connecting the handle so it has just enough slack. Clean the flush valve seat of any debris or buildup.

Professional Help for Kohler Highline Toilet Installation

If you encounter any issues during your Kohler Highline installation that you can’t resolve yourself, don’t hesitate to call in a professional plumber. Here are some signs it’s time to contact a pro:

  • The floor flange is badly corroded or needs replacing.
  • Your bathroom has an uncommon or difficult plumbing configuration.
  • Leaks persist even after multiple repair attempts.
  • You don’t feel comfortable completing any part of the installation.

Many plumbers offer toilet installation and replacement services at reasonable rates. They have the skills, experience, and tools to quickly troubleshoot any toilet issues. This can save you time, frustration, and potential water damage.

Frequently Asked Questions About Installing a Kohler Highline Toilet

Here are answers to some commonly asked questions about Kohler Highline toilet installation:

How long does it take to install a Kohler Highline toilet?

Expect the installation to take 2-4 hours for most DIYers. Having another person assist can speed up the process. Professional plumbers can usually complete the job in 1-2 hours.

Do I need to replace the toilet flange when installing a new toilet?

The existing flange can usually be reused unless it is loose, badly corroded, or damaged. If it is even with the floor level, adding a flange extender is recommended to get the right toilet height.

How do I remove the old bat-wing style bolts on the flange?

Use a chisel or flat pry bar to bend back the wings. Then twist and pry the bolt head free using locking pliers or a vice grip. Clean off old putty before installing new bolts.

Can I install my Kohler Highline toilet myself?

Yes, installing a new Kohler Highline toilet is a DIY project that most homeowners can tackle themselves with some patience and plumbing know-how. Make sure you have the right tools and materials. Call a pro if you encounter any issues.

What height is standard for a Kohler Highline toilet?

The standard height measures around 15 inches from floor to bowl rim. Comfort height models are 17-19 inches high. Ensure you have the right measurements for your bathroom.

How do I adjust the water level in the Kohler Highline tank?

Turn the adjustment screw near the bottom of the fill valve clockwise to raise the water line or counter-clockwise to lower it. Adjust so it’s 1 inch below the tank overflow tube.


Installing a Kohler Highline toilet greatly improves the look and performance of your bathroom. While it takes some work, the job can be completed by most DIYers with proper preparation and tools. Just take your time, follow all the steps, and don’t be afraid to call a professional plumber if any issues come up. With its clean curves and efficient flush, you’ll quickly appreciate the upgrade your new Kohler Highline toilet provides.