Garage Toilets: Can You Add a Bathroom to a Garage?

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You’ve made your garage a cool space you never want to leave….except when you have to go. Why not put a toilet in your garage, so you don’t have to?

We spend more and more time in our garages lately, and this site is all about making it extraordinary.

There are many great reasons you’re considering putting a bathroom in your garage, especially if your garage isn’t attached to your house.

But you’re probably wondering if you can install a garage toilet and what’s involved in the process.

You can put a toilet in your garage but will almost always need a permit to begin work. You’ll need to follow specific Building Code guidelines for the size of the bathroom and how much space to leave around the toilet. You’ll also need to consider the cost of any structural changes required to add the plumbing. Adding a bathroom to a garage is a substantial project and requires meticulous planning and approval from your local municipality.

This article isn’t intended to be everything you need to know to add a bathroom to a garage, but it can serve as an overview.

Many details depend on your local municipality, so I recommend checking with your local planning office before you start ripping up your garage to add a bathroom. Even if you don’t need a permit, it’s better to check before you begin than after you’re done.

Nobody wants a surprise visit from their local building inspector.

Building Codes for Adding a Bathroom to a Garage

You must start with the residential building codes that apply to your area. Seriously…this isn’t something you want to skip.

In most areas, the International Residential Code (IRC) will apply. However, there are almost always local or state\provincial regulations that apply as well.

The ICC’s great interactive website lets you pull applicable code documents for your state.

In addition to the residential codes, your municipality may have regulations prohibiting adding a toilet to your garage. This is especially common if it’s a detached garage.

Here in Florida, we need to pay special attention to any plumbing work that we do so that we don’t contaminate the local water system. Your state or township may have similar restrictions.

Additionally, be sure you’re allowed to make structural changes to your home.

Even if you are, ensure your proposed changes fit their guidelines. You want to avoid getting fined or being forced to remove your hard work a few weeks or even years after finishing your new garage bathroom.

Once you look at the building codes, it doesn’t hurt to know what kind of bathroom you’d like in your garage. It’s common to find regulations that allow some types of construction but prohibit others.

How to Add a Bathroom to a Garage

If you decide to build your garage toilet on your own, here’s the process you should follow:

Designing Your Garage Bathroom Layout

According to the International Residential Code, you must ensure 21 inches (53cm) of clearance in front of your finished toilet.

Other recommendations include the following:

  • There must be 15 inches (38cm) of space from the center of the bowl to the bathroom walls on either side of the toilet.
  • The clearance needed for the back wall has to be 12 inches (30cm) added to half the width of the toilet bowl.
  • The shower floor must cover a minimum area of 30 by 30 inches.
  • There should be 24 inches (61cm) of clearance in front of the shower entry (if applicable).

This layout is followed in most cities, but as I mentioned above, other local requirements could exist.

Designing a bathroom layout that supports all these recommendations while still making sense for your garage can be challenging. Still, keeping you in compliance with the building codes is essential.

Install Drainage Pipes

Your garage floor is likely on a concrete pad, but unless you have existing plumbing and drainage pipes, you will need to make some changes to the foundation.

With that, you have two options.

The first is to break through the floor, install your sewage tie-in and water pipes underground, and patch it when you’re finished.

The second option is to set your toilet on the shower on a raised platform that allows you to run drainage pipes through the wall and underground once outside.

It’s worth saying again: no matter which option you choose, ensure it adheres to your area’s building codes.

Toilet in a garage Pin

Providing Water Supply

The water supply for your garage bathroom will most likely come from underground pipes from your house.

As tempting as it may be, only run the pipes along the garage walls if you have an insulated garage. Otherwise, they could freeze and crack during the winter, potentially causing thousands of dollars in damages.

Professional plumbers recommend using a 3/4-inch pipe to ensure you have enough water pressure.

If you need hot water in the toilet (for whatever reason), installing a small water heater in your garage is better than running an underground pipe from your home’s primary water heater.

Not only is it more economical and efficient, but it also requires less piping.

Dealing With Ventilation and Humidity

You’ll need additional ventilation to deal with odor and humidity regardless of your setup.

Aside from the problems that humidity causes in your garage, the International Residential Code requires that either a window or dedicated ventilation be installed.

Proper ventilation ensures that the steam and moisture from the toilet won’t float around the space for long. This is important if you spend a lot of time in the garage instead of using it as only a toilet.

Painting the Walls

To help protect against mold, paint the walls in your garage bathroom with moisture-resistant enamel paint. Not only will this make the walls easier to clean, but it will also help stop mold growth.

While painting my garage, I tried several different paint types and colors. I explain the differences and offer recommendations in this article.

It’s one of the most popular articles on this site, so I know you’ll find great information there.

Before You Install a Garage Toilet…

Hopefully, this gives you an idea of how significant a project it is to install a bathroom toilet in your garage. It can easily cost thousands of dollars and takes a lot of planning.

Here are some things to think about before you get started:

Are You OK With Structural Changes?

You’ll almost certainly have to make structural changes to your garage, and you need to be OK with that.

It may require tunneling and trenching through your concrete garage floor into your yard or driveway. The location of your garage and proximity to your septic system or main sewer line will play a significant factor in the project.

This was a deal-breaker for me.

As much as I’d like a garage toilet, it’s not worth the work I’d have to do.

Do You Need a Professional?

If you’re the DIY type or have a lot of experience in construction and home remodeling, you may feel confident installing a garage bathroom on your own.

Otherwise, I highly recommend having a professional do the job.

Remember, this could be an expensive project and not a good time to learn by trial and error.

Consider Alternatives

If digging through the concrete floor in your yard is unrealistic or too expensive for you, consider fitting your garage toilet with a macerating plumbing system. 

This above-floor plumbing technology will pump waste through a small-diameter piping structure. It won’t require you to dig up your floor.

Garage Bathroom: Final Thoughts

You can put a toilet in your garage as long as the building codes in your city allow it and the structure of your property supports it. Take some time to weigh your options and consider the investment carefully.

Feel free to get professional help if you need help adding a bathroom to a garage.

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Tim Wells

Tim Wells, the founder of Garage Transformed, has been featured in dozens of home renovation publications, including, Home Stratosphere, House Digest, Livingetc, and SFGate. Since 2018, he has helped over two million people transform their everyday garages into something they can be proud of. He lives in Central Florida with his wife and bulldog.

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