Plumbing – What are the standard sizes/clearances for bathroom elements

bathroomplanningplumbing

I expect to be asking several more questions about this project; but I'm starting with a general one, and will get more refined as things develop.

We are working on finishing our basement, which includes a bathroom. In the original plans, the bathroom was 5' x 8'; which is very tiny. This matches the size and planned layout of a bathroom upstairs, so we've an idea how cramped it will be. We would like to enlarge it a bit, and move some things around to make it more… usable.

The uncertainty I'm running into is dimensions. For example, toilets are typically about 22-24" wide; but most people would be more comfortable with some clearance on either side. I'm uncertain how to estimate the space needed for a toilet. Similarly, counters are usually 24-30" deep; but putting in a sink typically defines a minimum cabinet depth. Finally, while the original plans called for a tub/shower (side entry), we're planning to change that to a corner shower. Tubs seem to be 30" wide; but I expect a corner shower to be wider (perhaps 36" x 36"). And if the shower has a corner entry, should I allow more space to enter/leave the shower?

Best Answer

Some of those minimum clearances are defined in building codes and will vary from place to place. In Ohio we use the International Plumbing Code (IPC) and it does define some of these minimums and local municipalities might add additional regulations. But it sounds like you may not be as concerned with the minimum specifications, what you really want to know is what "feels comfortable" and looks/feels good. Unfortunately a question like that is tough to answer.

Luckily people have been dealing with small bathrooms for ages so there are a number of strategies you can employ and there are some specialty fixtures that can help, like narrower bathtubs (28” instead of the standard 30”), shallower vanities/sinks, shallower toilets (10” rough-in instead of the standard 12”), etc.

If you can find a copy of the codes your area uses that can be a good resources if you have the patience to read it. I would recommend an electronic version so you can search for terms.

In the IPC the relevant sections I found are here:

Section 417.4 Shower compartments

All shower compartments shall have a minimum of 900 square inches of interior cross-sectional area. Shower compartments shall not be less than 30 inches in minimum dimension measured from the finished interior dimension of the compartment, exclusive of fixture valves, showerheads, soap dishes, and.safety grab bars or rails.

417.4.2 Access. The shower compartment access and egress opening shall have a minimum clear and unobstructed finished width of 22 inches.

Section 405.3 Setting

405.3.1 Water closets, urinals, lavatories and bidets. A water closet, urinal, lavatory or bidet shall not be set closer than 15 inches from its center to any side wall, partition, vanity or other obstruction, or closer than 30 inches center-to-center between adjacent fixtures. There shall be at least a 21-inch clearance in front of the water closet, urinal, lavatory or bidet to any wall, fixture or door. Water closet compartments shall not be less than 30 inches wide and 60 inches deep.

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