3 Inch or 4 Inch: What Size Pipe is Best For Your Toilet Drain?

A larger toilet drain pipe makes waste removal smoother. However, not everyone would need a larger pipe as things aren’t the same for every house. 3 inch pipes are mostly used for carrying water. But these are also used in small houses, as 4-inch ones can prove to be too large for their needs.

If you aren’t sure whether a 3 inch or 4 inch toilet drain pipe you will need to buy, we’re here to help you decide.

3 Inch or 4 Inch Toilet Drain: Which One is Better for Whom?

Though a 4-inch pipe can easily carry out almost twice as much waste as the 3 inch one, you still have to consider some facts before choosing a standard toilet drain size for your toilet.

A 3-inch pipe works for carrying the water while 4-inch pipes move wastewater to avoid clogging and put it in a sewer tank.

Supporting multifamily units, 4 inches is a good choice, but larger diameters can be needed in the case of large apartments or industrial buildings.

What Is Standard Toilet Drain Pipe Size?

Plumbing pipes of different diameters carry toilet water to the septic tank. Normally, 3 or 4 drain for the toilet can be used —however, a 3 inch is considered to be a standard size for the toilet pipes.

Moreover, a 4-inch toilet pipe can handle more waste from several toilets. Or you can install a 3-inch toilet pipe along with the main 3 or 4-inch toilet drain pipe, and directly connect both the pipes to the septic tank.

How Do You Measure a Toilet Drain?

If you want to know how big the toilet drain pipe of your toilet is, you have to measure it. As the inner diameter of the pipes can be clogged or get smaller day by day, you have to measure the outer diameter to know the actual size. Normally toilet drains are measured in inch/imperial unit or metric unit.

Can a Toilet Drain into a 2-Inch Pipe?

While draining a shower stall or washing machine, a 2-inch pipe can be used. You can use this as a vertical stack for any kitchen or basin sink.

Are All Toilet Drains the Same Size?

Not all drain pipe sizes will get you the same results. A 3 or 4 inch toilet drain is normally used in this modern age where only 3-inch pipes were used previously.

The diameter of the pipe is considered as the unit of measurement.

What Is the Standard Distance from the Wall for a Toilet Drain?

The older toilets maintain a distance of around 10 to 14 inches from the wall for a toilet drain. But 12 inches is enough for modern toilets, where any wall-mounted toilet also needs a 10-inch thick wall to maintain a proper flushing system.

Apart from that, We recommend you to read our article on Standard Toilet Rough-In Size, definitely worth reading it.

Final Verdict

Now that you know if you need a 3 inch or 4 inch toilet drain pipe, you can opt for the right pipe size for smooth removal of wastes. Be sure to periodically check the drain condition to make sure things don’t become too complicated to fix later.

Hello, I'm Jon C. Brown, an expert in the field of toilets. With over 15 years of experience in this industry, a significant portion of my life has been devoted to crafting high-quality toilets and bathrooms. Consequently, I've received countless inquiries about the toilet and bathroom industries. That's why, I've launched this website to provide top-notch solutions for all your toilet and bathroom related needs.

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