A garage can be so much more than just the place you park your cars and store all the stuff you’ve accumulated over the years but don’t really use. You could use the extra space more judiciously and convert your garage into a rentable living unit, guest room, or home office. Of course, adding a bathroom to the garage will need to be a crucial part of this home renovation plan. Here are some garage bathroom ideas and costs to help you get started.

Adding a bathroom to your garage

Adding a bathroom garage

Adding a bathroom to your garage is a possibility, irrespective of whether your garage is a stand-alone garage or is attached to your home. 

However, adding a bathroom to a stand-alone garage may require special building code permits, depending on where you live. So always check with your local building authorities before starting the renovation process.

Here are some important considerations for you to keep in mind while planning to add a bathroom to your garage.

Read more: Turn garage into gym

The layout

You will need to make sure you plan your bathroom layout in keeping with your local community needs and regulations. A lot of communities adhere to the International Residential Code for space clearance requirements to help decide on layout and plumbing spacing.

According to this code, you will need at least 21 inches of clearance in the front and 15 inches on either side of the toilet bowl to install a toilet. The distance from the back is calculated by measuring the rough-in distance and adding half the bowl width.

A shower entrance should have at least 24 inches of clearance in the front. The shower area by itself should be at least 30×30 inches.


bathroom drainage

If your garage has been built on a concrete pad, breaking through the pad in order to install drainage pipes and then patching up the floor is a viable option.

Alternately, you could place your toilet and shower on raised platforms, allowing you to run drainage pipes through the wall and underground once they reach outdoors.

The pipes need to maintain a  gradient of a ¼ inch-per foot-slope until they tie in with the main sewer line. If it isn’t possible for you to maintain that slope, consider installing a macerating toilet capable of pumping waste uphill to the sewer. 

Water supply

You will need to evaluate the capacity of your home’s existing plumbing and water heaters to determine whether your existing system can handle the hot and cold water supply to your new garage bathroom. 

Ideally, hire a plumber to check your home’s plumbing. You will also need to check if the existing pipes in your home will work well with the new pipes installed in the garage bathroom.

Once you’ve confirmed your in-house plumbing is compatible with the new pipes, you can plan to draw water to the garage bathroom from your home by running underground pipes. Prevent the pipes from freezing in the winter by bringing them up through the garage floor instead of running them along the side of the garage.

Using a ¾ inch pipe to supply water will help you avoid water pressure problems. It may also be more convenient and economical to install a small water heater for the new shower instead of installing a pipe from your main water heater to the garage.

An easy way to reduce water wastage and make the bathroom environmentally friendly is to store bath water from your shower and redirect it to the toilet flush.


bathroom vent

Ventilation is important for any bathroom. Your garage bathroom will need a window that provides a minimum of one and a half square feet of flow space as well as an exhaust fan to ensure steam from the shower as well as bad odors escape. 

Another necessity is to paint your bathroom walls with easily cleanable and moisture-resistant paint to avoid the growth of mold.


Adding a simple bathroom to your garage will put you down between $3,000 and $6,000. However, if you want added luxuries, or if you need new water and sewer lines to add your bathroom, expect costs to rise exponentially, all the way to the $25,000 mark. 

Hire the best contractors in your area to help you with your home renovations. Click here to know more.

Garage bathroom ideas and costs was last modified: October 11th, 2022 by Narayan Shrouthy
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A full bath in the garage is great. No more tracking dirt through the house when you come home from working in the field, or on your car, or hunting, etc!