Can You Install a Toilet Next to a Kitchen?

Call it a powder room, a half bath, guest bathroom, or lavatory, a small bathroom in a public area of the house is always a good idea. You can let your guests feel comfortable in your home without letting them traipse through your private space. But what if your house does not have a half bath?

Can you install a powder room with a toilet next to your kitchen? You can install a toilet next to the kitchen, but there are several factors to think about. Space requirements, building codes, and plumbing requirements all play a part. You are allowed a toilet next to your kitchen, but it is not going to be easy.

We will take a look at the necessary requirements you need to comply with to install a half bath next to a kitchen so that you can decide if this is something you want to pursue.

Building Code Requirements

At one time, building codes required there to be two doors between the kitchen and toilet. Many people still believe that you are not allowed to locate a toilet next to a kitchen. However, building code rules have relaxed over time. The rules permit a bathroom to be located next to a kitchen if the construction meets the following requirements.

• There must be a door between the bathroom and the kitchen. This is self-explanatory. The room where you cook and serve food should have a physical barrier between it and the bathroom.
• The bathroom must have a sink for handwashing. Again, this is as much common sense as building code requirements. You need a sink next to the toilet because everyone needs to be able to wash their hands after using the bathroom.
• The new installation must meet all the other requirements for plumbing, which include rules about fixture spacing, ventilation, drainage, and ventilation.

While the first two requirements are easy to meet, most people don’t know the ins and outs of plumbing codes. Let’s dive a little deeper into the plumbing requirements that apply to a new bathroom.

Spacing

Building codes require particular spacing for plumbing fixtures in a bathroom. The center of the commode must be at least 15 inches from walls or cabinets. You also need 21 inches of open space in front of the toilet. The separation between the sink and toilet must be at least 30 inches from center to center. Many experts recommend a couple of inches beyond this, but these are the minimums required by law.

If you want your new bathroom to be compliant with the Americans with Disabilities Act (ADA), you will need 56 inches in front of the toilet and a rectangle 30 inches X 48 inches in front of the sink. The ADA is not required in home remodels, but this is something to be aware of. ADA bathrooms require lots of floor space that might make your kitchen harder to use.

When you think about adding a toilet to a half-bath near your kitchen, you will have to think through the spacing requirements when planning. It’s not just the toilet you must account for. You need to have room for the sink and space for the door to swing. You also need to make sure you can allow adequate space around the new plumbing, and for the door to open correctly. 

Ventilation

Bathrooms are required to use two different kinds of ventilation. The first is fresh, dry air in the bathroom. You can meet this requirement by installing a vent fan in the bathroom, or by including a window that can be opened. Some locales require both; you’ll need to check with your local government to be sure.

The second form of ventilation is required for the plumbing itself. Sewer lines are required to have a stack vent. The stack vent allows outside air to have access to your sewer lines. Most people are not aware of this requirement since the stack vents are hidden inside your walls and attics. If you go into your attic, you will find pipes leading up from each one of your plumbing fixtures.

The sewer lines leading away from both the sink and toilet must have stack vents that let outside air into the drainage pipes. Some building codes allow every drain to tie into a single main vent for the house, while others require separate external vents located within five feet of the plumbing fixture. This is another item that you will have to confirm with your local government. 

Installation

Meeting building codes is only half the difficulty of installing new plumbing fixtures. The other part is adding incoming water lines and outgoing sewer lines. You absolutely must get the sewer lines installed correctly. The sewer line must have the correct pitch, or it will not drain correctly. This is no place to be close. The line must work.

The key feature of making a toilet drain properly is the slope of the sewer line leading away from it. You need ¼ of an inch of drop for every foot of pipe run. If the slope is too steep, the toilet won’t pull the proper vacuum suction when you flush. On the other hand, if the slope is not steep enough, the sewer line will not drain at all. 

If you have a slab floor, often the easiest way to achieve this slope is to elevate the base of the toilet a few inches, then run the sewer line through the walls. You can route the line to the nearest outside wall, then let it drop more steeply to connect with the sewer line outside your house. Running pipes through walls is significantly easier than running through slabs. 

If you can’t go through the wall, the other option is to run the line through the slab. You can either dig through the slab and run a tunnel from the new sewer line to the existing sewer, or you can bust a channel in the slab and lay the pipe in concrete. Neither one is particularly easy.

If your house sits on a pier and beam foundation or a basement, you have a much easier route. You just run the pipe under the floor in the crawlspace or basement. Make sure you have the slope correct, and you are good to go.

You also need a sewer line connected to the sink. This can tie to the toilet line; you don’t have to cut two holes in the wall or foundation to get the sink to drain.

Bringing Water In

Of course, all this sewage line requires water coming in as well. Bringing water into the bathroom is considerably easier. Since the water is under pressure, the slope of the pipes is not important. You can branch the incoming water lines from the kitchen’s water supply. You will need both hot and cold lines for the sink, while the toilet only needs to connect to the cold line.

The lines can be run through the existing walls to bring the pipes to the new bathroom. PEX pipe is an excellent choice for this. It’s somewhat flexible, so it is easier to work through holes in wall studs than PVC or other rigid pipes. You will need to get the proper fitting to connect the PEX to your existing plumbing, but that’s not too difficult. PEX is very forgiving and easy to work with.

Putting It All Together

Building codes allow you to create a new half bathroom next to a kitchen, but it is not a small project. Sewer lines and concrete foundations are both unforgiving. It’s easy to damage one or both in the process of adding a new bathroom. Unless you are an experienced plumber or have supreme confidence in your construction skills, this is a job for a pro.