🚽 The Measurement Method for the Hole Distance Between the Toilet Sewage Pipe and the Wall

📐 What Is “Hole Distance” or “Rough-In”?

• Definition: The horizontal distance from the finished wall surface to the center of the sewage outlet pipe on the floor.

• Common Sizes: 300 mm and 400 mm are the most standard. Some homes may have 305 mm, 350 mm, or even 450 mm.

🛠 Tools You’ll Need

• Measuring tape (preferably metric)

• Pencil or marker

• Notepad or phone to record measurements

• Optional: flashlight (for dark corners)

📏 Step-by-Step Measurement Guide

Step 1: Locate the Sewage Outlet Pipe

• Find the circular drain hole on the bathroom floor where the toilet will be installed.

• If the toilet is already installed, you may need to remove it or measure from the visible bolts.

Step 2: Identify the Finished Wall

• Measure from the finished wall surface, not the baseboard or studs.

• If tiles are installed, measure from the tile surface.

Step 3: Measure the Distance

• Place the measuring tape at the center of the sewage outlet pipe.

• Extend the tape straight back to the wall.

• Record the distance in millimeters.

✅ Tip: If the wall is not yet tiled, subtract 20 mm to account for tile thickness.

📊 Reference Table for Toilet Selection

🖼️ Visual Guide

Here’s an illustration showing the correct way to measure:

 

• The arrow shows the distance from the wall to the center of the sewage pipe.

• Labels indicate standard rough-in sizes: 300 mm and 400 mm.

🧠 Final Tips

• Always measure twice to confirm accuracy.

• If your measurement falls between two standard sizes, choose the smaller rough-in and use a toilet offset flange if needed.

• Consult your toilet’s specification sheet before purchase.