What’s The Proper Toilet Waste Height?

While installing a toilet can get rather crappy (I amuse myself more every day), it’s not an overly hard job. Perhaps the most important two parts of the job (aside from having a toilet) are knowing the proper toilet waste height and what that means. Now, this is gonna be a nice, short, and informative article. We’ve got a single question and a few secondary queries to add, so let’s get right into things.

The “proper” toilet waste height (pipe size) is 190 mm, though this depends both on your toilet and your home’s plumbing.

There’s a little bit to break down here, so let’s get going, shall we?

Toilet Waste Height: Basics

When you begin to install a toilet, there are a few important measurements to take. First and foremost, you need to know how big (width, height) the toilet itself is. With that in mind, you need to know how high your floor is, where the nearest flange is, and how high you want to mount the toilet.

This is for a few reasons: first, the size of your toilet will affect where and how you hang it (obviously). Second, the finished height of the floor (if unfinished when installing your toilet) will affect where and how you mount the toilet as well. Finally, the distance to your nearest flange will affect how much the toilet waste pipe needs to be cut to fit properly.

When you first install the toilet waste pipe, it’s good practice to have a bit of wiggle room in terms of size. This allows you to make last-minute adjustments that you simply wouldn’t be able to otherwise. For example, let’s say you’re finishing up your floor and realize it’s 2-3 cm higher than you thought. If your toilet waste pipe is too short, you’re screwed. But if it’s ~10 cm too long, you can cut it down without an issue. The same logic goes for the distance from your nearest flange, and for the mounting height of the toilet. You can change your mind and hang the toilet a bit higher if you have excess pipe – not so much if not.

How Tall is the Average Toilet and Waste Pipe?

The average toilet is between 35-38 cm from the floor to the top of the bowl.

While this obviously varies with each toilet, it’s a good baseline to start from. Now, a toilet waste pipe should be roughly 15-16.5 cm (6-6.5″) above the floor. The rough plumbing is then cut down to size as needed when the closest flange is installed.

Waste drain pipes are generally 7-10 cm in diameter. In short, the wider your plumbing, the better it can handle waste. That means fewer clogs, more capacity, and better overall performance. A 10 cm pipe, for example, could carry (in theory) the waste of 2 toilets, unlike its 7 cm counterpart.

One more thing to note is the distance between your toilet and the main soil stack of the house. The main soil stack is generally a slightly larger pipe that reduces in size above the main bathroom, extending through the roof. It’s good practice to do your best when possible to keep your toilet within 2 metres of the main soil stack.

Final Thoughts

That was a nice, short one, yeah? While this isn’t the most pleasant topic of discussion, it’s an important one! Knowing the proper toilet waste height along with basic measurements to keep in mind will make your job much easier. Just remember – measure your toilet’s height and width, along with your floor’s height.

After that, knowing that the average toilet waste pipe is 190 mm, and should be roughly 15-16.5 cm above the floor is vital. Finally, ensuring your waste pipe is slightly longer than needed allows a good bit of wiggle room. It’ll let you adapt on the fly if needed without needing to scrap all of the work you just did. And remember – if you’re unsure of your ability to install a toilet, please – call a plumber. It’s their job to make your life easier, so let them do it! They get the less fun work, and you get to sit back with a drink while they do.

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About the Author Harry Thompson

Involved in home renovations throughout his life, Harry is an expert in everything to do with home and garden DIY. In his spare time, he enjoys cooking and tending to his garden.