Best Toilet for 13.5 Inch Rough in Toilet Replacement

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Sometimes you come across an odd toilet rough-in size like 13.5 inches from the wall to the toilet flange drain hole. In such a situation it will be ideal if you can buy and install a 13 1/2 inch rough in toilet instead of going for a 12-inch rough-in toilet I see many people resort to as a last option. Fortunately for you, I was able to find a 14-inch rough-in toilet model that can be installed even on a 13.5-inch rough-in.

Here is that best toilet for 13.5 inch Rough in toilet replacement.

* Kohler K-3949-0 Highline Comfort Height Elongated Toilet (Check at Amazon #ad)

Kohler K-3949-0 for 13.5 Rough in Toilet Replacement

This Kohler K-3949-0 toilet model (link to its Amazon page #ad) is designed to be used as a 14 inch rough in toilet. However, when you install it on an exactly 14-inch toilet rough-in, it leaves a gap of 3/4″ (0.75″) inches between the tank back and the wall.

Below is the diagram from the Kohler K-3949-0 specification sheet that shows the gap of 3/4 inches between the tank back and the wall when installing on a 14″ rough-in. (See where pink arrow points)

13.5 rough in toilet

This toilet model is bit expensive but is ideal for your non-standard 13.5 rough in size issue. The toilet comes from Kohler which is a very good toilet brand and the features are good. It has a taller Comfort Height seating position which is easy for adults and even people with disabilities. The elongated toilet bowl makes is more comfortable to sit on and provides better thigh support. It also offers more space to clean yourself than the old round bowl toilets. I checked its customer reviews and ratings online and they seem to recommend this as a good toilet to buy.

Another advantage of this Kohler model is it will leave a small 1/4 inch (0.25″) gap between the toilet tank back and the wall. Having this gap is good because it will prevent mold and mildew that form when toilet tanks touch the wall.

I hope this helps you. I see many people buy and install 12-inch rough-in toilets when they have a 13 1/2 inch rough-in. When you install a 12 inch rough-in on a 13.5″ rough-in, you get a large and very noticeable gap between the toilet tank and the wall. So your toilet placement will look odd. Also this gap increases the length of space taken up by the toilet. So, installing the above Kohler toilet will help you avoid these issues and save you space too.

Best Toilet for 13 inch Rough in Toilet Replacement?

Now, what do you do if you have a slightly smaller rough in size that needs like a 13 inch rough in toilet? Ideally, it would be great if we can find a 14-inch toilet model that fits even a 13 inch rough in. So I checked the specification sheets of all the 14 inch rough in toilet models for sale in the US market.

Fortunately, I found one 14 inch toilet that will fit a 13 inch rough-in situation. It is the American Standard Cadet PRO Compact Right Height Elongated 14″ Rough-In 1.28 Gpf Toilet (Check its Amazon page here #ad). If you take a look at the diagram on its specification sheet here you can see that when its installed on a strict 14 inch rough in, it leaves a gap of over one-inch (1-1/16″) between the toilet tank top and the wall. So this Cadet Pro toilet should just fit a 13″ roughin.

Can I Use A 12 Inch Rough In Toilet On A 13 Inch Rough In?

Though the standard rough-in size is 12 inches, most of them are not exactly 12 inches. Some are 11.5 inch rough-in’s and some are 12.5 inch rough-in’s. So most of the 12 inch rough-in toilets are designed to fit even 11.5 rough-in size or in some cases like some of the latest Toto Drake models, even 11 inch toilet rough-ins. So when you install them on a larger 13-1/2 inch rough in, you get a large gap between the tank and the wall.

So if you are thinking about installing a 12 inch rough in toilet on a 13 or even 12.5 inch rough in I recommend you find and installed a 12 inch rough in toilet that hardly leaves any gap between the tank and wall when installed on 12″ rough-in. So, if you install such a toilet on a 13 inch rough-in, you’ll only have a gap of 1-inch between the tank and wall.

So far, I’ve found only one 12 inch rough in toilet model that can be great for 13 inch rough in sizes. It is the Kohler K-3654-0 Persuade Two-Piece Elongated Toilet ( page link #ad). According to the Kohler K-3654 specification sheet here this model needs a strict 12-inch toilet rough-in or more, otherwise you can’t install it. (See the diagram and “Installation Notes” in the spec. sheet.) Check these comments and replies on Amazon here #ad about its roughin size that further confirms it’s a strict 12-inch rough from the finished wall. It is also a high profile and beautiful toilet.

One inch gap between tank and wall is normal. Many toilet models leave a one-inch size gap even on standard rough-in sizes like 10, 12 and 14 inches. Having a gap like this will also allow you to clean the back of the tank and avoid issues like, mold and mildew growth that happen when toilet tanks are too close and touching the wall.

4 thoughts on “Best Toilet for 13.5 Inch Rough in Toilet Replacement”

  1. Hello – your post said “However don’t despair. I found several good 12 inch rough in toilet models that can be great for 13 inch rough in sizes. I recommend them, because when installed on a 12 inch rough in these below models hardly leave any gap between the tank and wall. So if they are installed on a 13 inch rough in they’ll only have a gap of 1-inch between the tank and wall.”

    Could you share – what are the names of the 12 inch rough in toilet models that will leave only a one-inch gap if the flange is a 13 inch rough in?

    thank you

    1. Hi Jordan,
      Thanks for reminding me about missing to include those exact 12″ rough in toilets that will leave the shortest gap on a 13″ rough-in. I checked now but was able to find only the Kohler Persuade toilet that requires an exact 12″ roughin. I have updated the post with it’s details. I keep an eye on the market and if I come across any other exact 12″ rough in toilets or even a 11-3/4″ rough in toilets I’ll update it here.

  2. Clarence Williams


    It would seem, from your article that the Cadet Pro would be a better choice to use for a 13,5 inch rough-in since the gap to wall would be 9/16″ instead of 1/4 ” with the Kohler model. This additional gap would better allow for any tolerances on the actual toilets.

    Did I miss something??


    1. Agree with you. Though both fit 13.5″ rough-in, Cadet Pro is a safer choice as it allows for more tolerance.

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