Adding a Bathroom to an Apartment in NYC

by | Last updated Jan 22, 2024 | Apartment Renovations, Bathroom Design, Renovations

Can you add a bathroom to an apartment in NYC?

You can add a bathroom to an apartment in NYC if you have approval from your building management and Condo or Co-Op Board. You will also need to hire an architect and file for permits with the Department of Buildings. In New York City, adding a bathroom to an apartment is filed as an Alteration with the Department of Buildings.

Adding a bathroom in NYC is allowed by some buildings and not by others. If you plan to add a bathroom, check with your building management first. You will need to consult with an architect to establish the scope of work and determine if it is feasible.

I am Jorge Fontan, an architect in New York and owner of Fontan Architecture, a Manhattan-based architecture firm. We work on a variety of projects in our office, including interior apartment renovations. We get many inquiries from people wanting to add a bathroom to an apartment. In this post, I will review some key considerations when adding a bathroom and show a few examples from our projects. 


Adding a Bathroom: Building Management / Board Approval

Firstly, it is essential to check with your Condo, Co-Op Board, or building management company about their rules for adding a new bathroom in your apartment. Although there is no Building Code to prohibit this practice in NYC, some buildings have internal regulations that do. For example, the “Wet Over Dry” rule that some Building Boards impose. 

It is essential to review your alteration agreement before planning an apartment renovation. The alteration agreement is a contract between the Apartment Owner / Shareholder, and the building Board. We have another post if you would like to read more about Alteration Agreements


Wet Over Dry Rule

“Wet Over Dry” means you cannot have a “wet space,” such as a bathroom, over a “dry space,” such as a bedroom on the floor below. Wet Over Dry is not a Building Code imposed by the NYC Department of Buildings. The Building Code has no problem with wet over dry. It is an individual building’s rule by the Condo or Co-Op board. We have another post if you want to read about Wet Over Dry. 


Hiring an Architect

When adding a new bathroom, you will need to hire an architect. At our architecture firm, we have done this multiple times. You must also hire a general contractor and licensed plumber for all construction and plumbing work. This work will require approvals, permits, and inspections.


Bathroom Codes

The new bathroom must comply with all applicable building codes. This work is to be filed with and approved by the NYC Department of Buildings. There are many variables to consider, which is why you will hire appropriately qualified professionals. 


New Bathroom in Manhattan Apartment

Below is an example project where we reconfigured one bathroom and closet into two bathrooms and a laundry closet. We have another post you can see if you want to read about Adding a Washer Dryer to an Apartment in NYC.

This first picture is of the Master Bathroom which we reconfigured.

NYC Apartment Bathroom

NYC Apartment Bathroom

NYC Apartment Bathroom


This next picture is the new bathroom added to the apartment.

Small Second Bathroom

Small Second Bathroom


Bathroom Ventilation Requirements

The building code requires proper ventilation for all bathrooms. In NYC, this means having a window or a mechanical exhaust in the bathroom. If the location you plan to put your new bathroom doesn’t have a window, you can connect to the exhaust in another bathroom. You cannot add a bathroom in NYC without an exhaust or window.


Plumbing Work and Inspections

Plumbing inspections are one of the most common problems for getting sign-off upon completion of renovations. All plumbing work is to be performed by a licensed NYC Plumber. Before sign-off on the job, you will have to pass plumbing inspections. Ensure your bathroom renovation contractor is on top of these inspections.


Additional Considerations for Your New Bathroom

There are many other items to consider when adding a bathroom. Here are just a few:

Toilets require you to cut through the floor to run your drain, but if you get a wall-mounted toilet, you can run plumbing through the walls and not disturb the floor. We have another post if you want to see the Pros and Cons of Wall-Mounted Toilets. 

Showers require drains as well. Adding an elevated shower floor for draining purposes may be necessary. 

The new bathrooms should have a waterproof membrane and mold-resistant materials.

Manhattan Bathroom Renovation

Manhattan Bathroom Renovation


Bathroom Additions

Make sure you hire the right people when adding a bathroom to an apartment. This type of work requires planning and coordination. You will want to get it right the first time.

In this article, we reviewed some of the basic concepts with regard to adding a bathroom. This post does not assume to cover every possible issue or condition, but provides a general overview of the topic.


Thank You for reading our blog post on Adding a Bathroom to an Apartment in NYC.

I hope this was helpful. If you want to speak with an architect about a potential project, contact us at Fontan Architecture directly.


Contact Fontan Architecture


Jorge Fontan

Jorge Fontan

This post was written by Jorge Fontan AIA a Registered Architect and owner of New York City architecture firm Fontan Architecture. Jorge Fontan has earned 3 degrees in the study of architecture including two degrees from the City University of New York and a Masters Degree in Advanced Architectural Design from Columbia University. Jorge has a background in construction and has been practicing architecture for 20 years where he has designed renovations and new developments of various building types.