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A Guide To Installing A Bathroom In The Garage

Finding and adding functional spaces to new areas of your home is a welcome task to some homeowners. The process of adding a bathroom to your garage is utilizing these spaces and making them functional. This article will serve as a guide to homeowners that want to add a bathroom to their garages. 

Adding a bathroom to your garage can be done in the following 6 steps:

  1. Check your ICC Codes 
  2. Design and plan your bathroom
  3. Installation of the drainage pipes 
  4. Installation of the water supply 
  5. Wiring
  6. Installation of the ventilation

This article will provide you with an in-depth guide on how you can add a bathroom to your garage. Not only that, but it will also give you some tips and tricks to help you along the way. If you’re interested in reading more about creating functional spaces, then keep reading. 

How to add a Bathroom to your Garage

Garages are great places to add bathrooms. The reason is that they are at floor level and have access to the main house’s piping and drainage system. In addition, some garages tend to have exposed frames, making it easier to access the central house wiring system. 

The basic skeleton or the foundation of a garage makes it a great usable space. If you have an attached garage, then a bathroom will be a great addition. It will also be a lot easier to add the garage into the house. 

First things first, as you start with this process, you need to assess your garage. Give your garage a good clean and then assess its current state. Finally, when you have a good idea of the space and how you’ll work with it, you can properly start the entire process. 

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Steps to take when Adding a Bathroom to your Garage 

  1. Make sure to check your ICC codes 

This step is the most detrimental, and overlooking it comes at a price. The ICC or the International Code Council is a global source of codes and standards and building safety solutions. There are 15 international codes, and this article will look at the 2021 International Residential Code. 

By checking your local codes, you can confirm whether they allow you to build a garage or not. So why do municipalities do this? 

Municipalities want to preserve the nature of the community. Through prohibiting these renovations, they deny single-family houses turning into multi-unit structures. 

After confirming that your local code requirements don’t pose a problem to your garage take-over project, you’re good to go. Here are some codes from the IRC that you should consider for your garage bathroom: 

  • The toilet should have 21 inches of space in front of it 
  • There should be 15 inches of space from the center of the toilet bowl to a wall on the remaining sides. 
  • There should be 24 inches of space in front of the shower entry or door 
  • The shower floor should have a minimum area of 30 by 30 inches.  

 It’s time to assess the condition of your garage. 

These are the three factors you need to assess the state of your garage: 

  • First, looking for a plausible issue – these are issues that may affect the space you’ve allocated for your bathroom. It could be anything from water damage to infestations. 
  • Be sure to determine the level of electrical and plumbing service that will be required. 
  • Inspect the floor – make sure that you inspect the space where the bathroom will be present. Check for any damage on the floor and confirm whether or not you will require a new subfloor.
  1. Design and plan your bathroom 

Regardless of whether this is a bathroom in your garage, make some design considerations. For example, you may want the same design as your house to flow into the bathroom if you have an attached garage. 

Maybe the same style as the other bathrooms in your home. Or should you want a much different style, there are numerous styles to choose from in catalogs. Here are some bathroom design styles that can help you get started on making these decisions: 

  • The clean European style 
  • Traditional style 
  • Modern contemporary style 

This project will take a lot of time and money to complete. However, there’s no need to make it essential when you can make it a functional throne. The choice is yours, but the bathroom space would have considerable potential if not carefully maximized to its utmost potential. 

Once you’ve decided on your design style, it’s time to decide on the design elements you’ll want in your garage bathroom. Here are the design elements you need to consider for this type of project: 

  • Showers 
  • Sinks 
  • Toilet bowl 
  • Lighting 
  • Walls and Ceilings 
  • Flooring 

If you have more than enough space, you are welcome to add a cabinet or vanity. If you want to add a bathtub into the bathroom, there will be additional considerations. Nevertheless, if this list has the general elements you want in your garage bathroom, keep reading for more information. 

It is also imperative that you mark the area that will house the entire bathroom. You can measure and make it with tape. To be sure. Once completed, you can start making your alcove. 

You can use plywood to create the alcove skeleton. This way, you can move on to the next steps. First things first are to start with the drainage. 

  1. Installation of the drainage pipes 

This section will split into two parts, the shower and the toilet. They have different drainage systems and will require different needs. 

Here’s how the overall drainage for the shower will appear. First, you will need a hole where the drain cover will be. Next, the drain cover will be attached to the drain tailpiece. Finally, a rubber gasket that’s on the tailpiece slips over the drainpipe. 

This tailpiece will lead to the P-trap and, finally, the branch drain. So now, how do you add a hole to your garage? Are there any other alternatives to this process? 

You may have noticed that your garage floor consists of concrete. Here are the two ways you can utilize to get your drainage system in place. 

  • Break through the concrete floor, install the pipes and all the parts mentioned above, and finally seal it off. 
  • Use a raised platform. This platform will allow you to run the drainage pipes through the wall. The lines could lead underground or onto a branch drain. This method is helpful if you have an attached garage.

Your drainage system will include a closet flange; this mounts the toilet to the floor and connects the toilet to the drain line. The drain line will then connect to the main waste-vent stack. 

But since the garage floor is concrete, how do you get the toilet drainage system in place?  Just like the shower, you can utilize the two methods shown above. Or you can choose to add a macerator, aka a macerating toilet. 

A macerating toilet is great for homeowners that don’t want the expensive cost of adding piping. Instead, it uses a system known as the upflush toilet system. The system has a large container behind the toilet or in the wall. 

Once your business in the toilet is complete, the toilet sends the waste to the large container in the back. The container has blades that liquefy the waste in the toilet. This liquified waste is then pumped out of the toilet and into the main drain pipe. 

As shared earlier, a project of this size takes a lot of time, and it is pretty expensive. If you don’t have any pipes close by, you may have to lay the pipes yourself or use a macerating toilet if you cannot handle the cost. 

Plumbing is the central part of this project and must be committed before getting into any other steps. With the plumbing in place, you can start adding the lighting and any other design elements you want in your garage bathroom. 

If you already have pipes running, then you don’t need to worry. All you have to do is add a branch brain that leads to the main pipes in your house. It’s hitting two birds with one stone. 

And if you’re planning to replace an old sink with a new toilet, here’s a step-by-step guide I wrote on putting a toilet where a sink was!

  1. Installation of the water supply 

With your shower plumbing in, it’s time to consider how you’ll be getting the water to your new bathroom. The shower supply system consists of the following elements: 

  • The shower arm 
  • The shower pipe 
  • Cold and hot water supplies 

The shower arm extends from the wall. An elbow fitting (at the top of the shower pipe) connects the shower arm to the shower pipe. The pipe runs up from the faucet, fed by hot and cold water supplies. 

The hot and cold water supplies are in the wall, or they are underground pipes. Experts recommended running these pipes through the floor. This way, during winter, they are not susceptible to freezing. This freezing may create pressure and force the pipes to burst inevitably. 

Another way to prevent pressure-type problems is to use 3- or 4-inch pipes. These pipes decrease pressure loss. This way, your showers are running as expected. Nevertheless, the placement of these pipes is a huge factor in preventing this from happening. 

If you want to run the water supply pipes through the walls, make sure your garage is insulated. The same freezing problem arises if the water supply pipes are not adequately cared for during construction. 

Experts also recommended adding a small water heater near your shower. This method should reduce the process of piping water from the water heating in the main house. However, this recommendation may not apply to homeowners with an attached garage, and their central house water heater is in the garage. 

If so, the piping should be an easy process. If and only if your water heater is in the vicinity. If not, be sure to get a small water heater. It is economical and efficient. It will also help in cutting costs. 

  1. Wiring 

One of the design elements that you may want to add to your garage bathroom is lighting. Wiring will help you easily switch your lights on and off. For example, you can choose to have a vanity light or a ceiling light. 

Before getting into wiring, there are essential things to consider. First things first, you cannot DIY your wiring without an electrical wiring permit. There are legal implications of wiring in your own home. 

If you do not have any experience wiring or do not have an electrical wiring permit, kindly contact a professional. 

If you get into any issue, should you choose to continue, your insurance company will not cover the cost of damage. Therefore, it is detrimental that you check your jurisdiction before starting on any wiring. In some cases, you will need an inspection before you can start wiring. 

If you do have an electrical wiring permit, the chances are that you already know what you’re doing. If not, kindly contact a professional for assistance. 

  1. Installation of the ventilation 

The IRC, the International Residential Code, requires you to add a window or any form of decent ventilation in your bathroom. Not only is this a requirement from the body of law, but it is also crucial that you have a way to deal with any smells or humidity coming from your bathroom. 

If you’re someone that spends a considerable amount of time in your garage, you will need a form of ventilation in our toilet. If you are using your garage bathroom, the smells may be too much to handle in the long run. 

Adding a window to your garage bathroom is just like adding any standard window in your house. First, of course, you will have to make room for it by breaking the wall and buying window panels and window panes. But the process is still the same. 

There are numerous designs to choose from, but the most recommended are awning windows. They give privacy, and they open outwards. The awning windows can also come in different glass panes. They don’t have to be transparent if you want that extra bit of privacy. 

Remember to check your jurisdiction and IRC codes to ensure the types of ventilation required for your garage bathroom. You don’t want to be on the wrong side of the law. 


  1. Can you put a bathroom in a garage? 

Yes, you can put a bathroom in a garage. If you want to add a functional space into your garage, this solution is best for homeowners. Adding a bathroom into your garage is a great idea. However, it is not exactly a solo project. 

One thing to note is that you should check your IRC codes before embarking on this project. Some jurisdictions do not allow homeowners to add bathrooms. Be sure to check where you lie on the scale. 

It will take time, labor, and a considerable budget. Experts estimate that it could take a maximum of $20,000. But, of course, this may not be the case for everyone. The main issue is piping. If you do not have any pre-existing piping, you may need to add the piping. 

This part of the process is what’s mainly costly. Another part of the process that will need you to dig into your pocket is wiring. So, again, if you check your jurisdiction, the most likely cause is that you will need to request an inspection before wiring, and you will need an electrical wiring permit. 

Design elements are also part of your budget if you want your bathroom to match the rest of the house. Nevertheless, you can put a bathroom in your garage. 

  1. Can I put a toilet in my garage without planning permission? 

Unfortunately, no. The planning permissions will have the law on their side, and you will most likely have to pay fines or serve some other form of punishment. This punishment depends on your planning commission and the rules they have in place. 

The IRC codes have strict rules and strict punishments. It is essential, for your peace of mind and that of your family, to avoid these fines. They can chuck a lot of your budget. 

  1. Can I put a bathroom in my detached garage? 

Yes, you can put your bathroom in your detached garage. The only problem is that you won’t have the piping from the main house. Using the piping from the main house reduces time and costs. 

With a detached garage, you will have to lay in the new piping. Alternatives exist, that’s for sure. For example, for the toilet, you can use a macerator. However, there are no alternatives for the shower. So, again, the laying of new pipes will have to take place.