How To Add a Bathroom to a Garage in Orange County

Many people who own homes would like to maximize their living spaces. In many cases, this entails renovating the garage to gain additional square footage. Imagining a luxurious home office? Gymnasium? Workshop? Guest suite? The possibilities are infinite. And if you are designing a space where you or your loved ones will spend a great deal of time, you will want to make it as comfortable and convenient as feasible. With this in mind, you might want to add a bathroom to your garage

Whether you’re creating a full bathroom with a shower, sink, and toilet or a simple half bathroom, adding a bathroom to a garage is a complicated process. This is due in large part to structural considerations and plumbing and electrical system modifications. But if you hire a seasoned contractor familiar with the nuances of design and construction in Orange County and Southern California, you’ll have power and flowing water in no time. These tips will help you begin the process of planning the addition of a restroom to a garage. 

adding a bathroom to a garage

Here at GreatBuildz, a free service that connects homeowners in Los Angeles, Orange, Ventura, and San Diego Counties with reliable contractors, we speak to homeowners every day about how to add a bathroom to a garage – here are some ideas & tips to get you started.

Check local laws and acquire required licenses

Many municipalities and HOAs have regulations regarding the construction of living spaces in garages. For instance, some zoning regulations prohibit homeowners from parking on the street. Adding a carport or other parking solution may be necessary if you will no longer be able to park your vehicle in your garage as a result of your garage renovation plans. Consult a local architect, contractor, or building inspector prior to beginning the addition of a bathroom to ensure compliance with all applicable codes. 

In addition, many building codes mandate that homeowners obtain permits and other approvals prior to beginning significant home improvement projects. Failure to do so may result in fines and other penalties, such as requiring the householder to modify or even demolish newly constructed structures at their own expense. 

call research orange county remodel general contractor

Investigate the utilities and electrical systems in your garage

Once you’ve received approval to construct a garage bathroom, it’s time to contact a general contractor to assess your home’s plumbing and water heater capabilities. In some cases, it may be possible to bring water from your existing system to your new lavatory by installing pipes underground or within your walls. If adding a bathroom plumbing system to your garage is not feasible from your home’s existing supply, your contractor should be able to provide suggestions. 

In addition, they will be able to advise you on the optimal placement of new wiring and outlets for your garage restroom. 

Do not disregard the ventilation system

When constructing a garage restroom, it is essential to install an adequate ventilation system to prevent the buildup of moisture and steam. Typically, this involves installing a window of at least 1.5 square feet to increase airflow, as well as an exhaust fan in the ceiling to enhance circulation.

The paint you use can also affect ventilation. Moisture-resistant, glossy enamel prevents the growth of mold and fungus and is also simple to clean. 

Planning the design of the restroom

bathroom well lit blue tile

Using the information gained from the site visit, your contractor will begin to design potential garage bathroom layouts.

The majority of cities mandate that construction projects adhere to the International Residential Building Code, and individual states and municipalities also have their own regulations. The International Code Council maintains an interactive database of building codes for every state, which includes building standards for California and Orange County,CA. 

Related: Small Bathroom? How to Make the Most Out of Your Space

Bringing form and function together

The planning process is not entirely laborious. Now is the time to visualize the desired space and investigate design elements such as key features and fixtures. In terms of what can be included, the ceiling is the limit. 

Among the top bathroom design trends for 2023 are tech integration such as heated floors, smart toilets, and touchless faucets; universal design elements such as curbless shower entries and shower seats; and spa-like elements such as rainfall showerheads, mood lighting, and skylights. 

An interior designer with expertise in bathroom renovations can collaborate with your contractor to ensure that the final product is aesthetically pleasing and durable. The objective of designing a restroom like this is to achieve a balance between form and function.

How To Add a Bathroom to a Garage in Orange County 1

How to install a bathroom in a detached garage

If you have a detached garage, your project will most likely be more time-consuming and more expensive. Since the structure is not only detached but also typically located at a considerable distance from the residence, the majority of the additional cost is attributable to extending the existing utilities (plumbing and electrical) to the new space, as well as piping for drainage that can transport effluent to the main sewer line in the street. 

At times, routing the utilities from the house to the detached garage may not be the best option. For instance, it may be simpler (and closer) to connect to a point of water outside the home that is used for watering the yard. 

Nevertheless, given the spaciousness and versatility of a detached garage, it may be well worth the investment!

Locate a Reputable Bathroom Contractor

typing on computer search bathroom contractor

To add a bathroom to a garage, a licensed General Contractor is required. (B-license). Legally, only this category of contractor may undertake this form of project requiring multiple trades. (ie. electrician, plumber, carpenter, etc). Contact a bathroom remodeling contractor if you want to add a bathroom to your garage.

Meeting with one or more contractors will provide you with an approximation of the job’s reality and estimated cost. Verify that any legitimate contractor you’re considering for this project has a valid California State License Board (CSLB) general contractor’s license and proof of workers’ compensation and general liability insurance.

Total costs to add a bathroom to a garage

When constructing a garage bathroom, a starting budget of around $35,000 is reasonable, assuming all existing drainage and electrical systems are in working order. If your specific situation is a bit more complicated, or if you plan to use upscale finish materials and fixtures, your bathroom addition may cost between $50,000 and $60,000. 

One of the most expensive aspects of installing a new restroom in your garage is connecting the toilet, sink, and shower to the home’s waste lines. This requires excavating a foundation or opening a substructure and locating the existing wastewater system’s closest connection. Running the plumbing supply lines (both hot and cold water pipelines) from the nearest point is another significant expense. And most people neglect the fact that a new bathroom will require a roof-mounted vertical vent line. Clearly, the greater the distance between the garage and the house, the more expensive it is to run all the utility lines.

Related: Average Bathroom Remodeling Costs in Orange County

How To Add a Bathroom to a Garage in Orange County 2

How long does it take to construct a bathroom in a garage?

Depending on the complexity of your bathroom addition and the location of the property, you may be required to create building plans. This will necessitate the employment of an architect; alternatively, a reputable contractor can usually bring their own preferred design team. Choosing your preferred floor plan, developing the plans, and obtaining the necessary approvals through the plan review procedure of your building department will typically take a couple of months. 

Once plans have been approved and permits have been obtained, construction can begin. Construction time for an attached garage bathroom addition is approximately six weeks. If trenching is required or there are other complications, your project could take up to two to three months to complete.

When it comes to remodeling your home, you shouldn’t have to go it alone – GreatBuildz can help simplify your renovation experience as you add a bathroom to a garage.


GreatBuildz is a free service that connects homeowners in Los Angeles, Orange County, Ventura or San Diego with reliable, thoroughly screened general contractors and provides project support from start to finish. Call now (818.839.6855) to chat with a real person about your next remodel project or visit our website for more information:

Hi, we're Paul and Jon - Co-Founders of GreatBuildz. We believe everyone deserves to find a great contractor, have a stress-free renovation, and enjoy their beautiful new space. There are so many contractors out there and it's often hard to tell the good from the bad... until it's too late. We started our company to help simplify your contractor search and help you have a stress-free renovation experience. We're always available to help, no matter where you are in the process. Click here to learn more about our story.

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