Bathroom Layout Guidelines

When planning a new layout for a bathroom, several factors have to be taken into account. Specific codes exist that regulate the placement of fixtures such as toilets, bathtubs, or sinks in the bathroom. These guidelines exist to ensure that the finished bathroom is both practically designed as well as safe. It is also important to know what categories bathroom layouts fall into. Below you will find information on the codes and regulations for different fixtures as well as categories of bathroom layouts.

Toilets

- No other fixture is allowed to be within 15 inches of either side of the toilet’s middle point.

- The space between a toilet and the fixture next to it must be at least 4 inches.

- There must be at least 24 inches of uninterrupted space in front of the toilet, and at least 36 inches between the toilet and the opposite wall.

*An exception to this rule: the path of an opening door may swing through the 24-inch space in front of the toilet.

- When separating the toilet from the rest of the bathroom, the enclosure must be at least 36 by 66 inches.

Sinks

- Sinks need a distance of 15 inches from the midpoint to a wall.

- If two sinks are installed, they must be at least 30 inches from the each other’s centerline.

- There must be at least 2 inches between a sink and another fixture.

- A sink cannot be placed on an opposing wall from a toilet unless there is at least 36 inches between the two fixtures. This does not apply if existing fixtures from an old bathroom are being replaced.

Showers

- Showers need at least 24 inches from the entrance of the shower to the nearest wall or fixture.

*30 inches is recommended for easier access.

- The shower stall itself must have an area of at least 34 by 34 inches, however at least 36 by 36 is recommended.

Bathtubs

- Bathtubs need at least 21 inches from the open side of the tub to a wall or fixture.

*30 inches is recommended for easier access.

- Most bathtubs are about 60 inches long by 32 inches wide, but can be as large as 72 inches by 48 inches.

- A corner bathtub is around 60 inches by 60 inches on average.

BATHROOM DESIGN TERMINOLOGY

-  Half bathroom consists of only a toilet and sink.

- Three quarters bathroom consists of a toilet, sink and shower, but does not have a bathtub.

- Full bathroom has a toilet, sink and combination bathtub/shower.

- One and a half bathroom has a toilet, sink, bathtub, and shower fixtures.

*Shower and bath fixtures are separate in this design

OTHER SPECIFICATIONS

Drainage & Vent Pipes

Drainage and ventilation pipes can be made out of PVC or ABS pipes. This is usually a matter of contractor preference. While PVC has a higher level of heat resistance from sunlight than ABS does, the ABS has a wider range of chemical resistance than PVC.

- Toilets need at least a 2- or 3-inch wide drainage pipe.

- As most toilet drains are at the 12-inch mark, drainage pipe should be installed 12 inches from the finished wall. (Roughly 13 inches from drywall.)

- Toilets need at least 2-inches of ventilation pipe.

- Sinks require a 2-inch wide or larger drain that will intersect with a 3-inch wide horizontal run.

- Sink drains should be installed at least 19 inches above the floor to be compatible with standard sink height.

- Sink vent pipes should be at least 2 inches in diameter.

- Bathtubs and showers require at least a 2-inch wide drain that intersects with a 3-inch wide horizontal run.

- The main stack is the central pipe all drain pipes connect to. These should be at least 3 inches in diameter.

Supply Pipes

Older supply lines may have been made from copper so if you find yourself replacing existing fixtures it may be required to purchase copper parts. If installing a new bathroom entirely, current commonly used parts are made from PEX pipe.

- Bathtub/shower supply lines are usually 1/2-inch to 3/4-inch in diameter, depending on the valve.

- Sinks and toilets tend to have a standard 1/2-inch diameter pipe.

- If installing a stub out for a sink, it should be 19 inches above the floor. If there are two sinks, the stub outs need to be at least 8-10 inches apart.

- If installing a stub out for a toilet, it should be at least 8 inches above the floor.

Tub and Shower Fittings

- Tub controls should be at least 26-28 inches above the floor.

- The tub spout should be at least 6-8 inches above the top edge of the tub.

- The shower head should be at least 74-76 inches above the floor.

- The flow/temperature control for the shower needs to be at least 46-48 inches above the floor.

CONCLUSION

It is important to remember that the figures above are general guidelines, but do not apply in all situations. It would be wise to research local plumbing codes for specific regulations on distances. Whether you are remodeling an old bathroom or designing a new one, it is important to be economical with the space available. It is equally important to find a balance between functionality and convenience, while adhering to local regulations.