Does US building code allow a toilet or sink to be placed in the clear floor space on the side of a tub?

Question

I'm trying to understand the building codes used in the US and specifically NJ for the clear space in front of a shower or bathtub. This is for a residential single family home.

I remember reading that there needs to be 24" of clear floor space for the tub. It does not specify if the entire length of the tub needs to be clear. For a shower you just need 22" wide by the door. For an accessible bathroom you only need 48" along the tub.

There are a lot of bathroom designs I see that have either a toilet or a sink next to the tub.

Can you put a toilet or sink next to a bathtub so that the center of the toilet/sink is at least 15" away from the edge of the bathtub even though it's in the clear space? Or does the clear space need to be the entire length of the tub? Does it matter if the toilet is next to the controls or not?

If not what are the minimum clearances for the dimensions shown below?

Answer 1

I'll pretend that you're operating under the International Residential Code (IRC), which you probably are. Yes, you can put the toilet in the bath's clear space. No, it doesn't matter if the toilet is at the same end as the tub controls (there's a tiny exception if you have a tub skinnier than 30 inches wide, see below).

(1) The toilet needs a 21 inch clear space in front of it (IRC 307.1). That's the minimum for your drawing's 2'-6".

(2) The toilet needs 15 inches of clear space from center to edge of tub (IRC 307.1), confirming your 1'-3". There's an obscure requirement in IRC P2705.1 that center of toilet must be at least 30 inches from adjacent plumbing fixtures like your tub's spout or a sink faucet. The typical tub width of 30 inches puts center of spout at 15 inches from the tub edge, so the requirement is typically satisfied by the 15 inch tub edge to toilet center (15" + 15" = 30"), but skinny tubs do exist and a pedantic building official could cause you some trouble if you're not cognizant. (This is the "tiny exception" from my intro, where a skinny tub with controls opposite from the toilet end can have the toilet at your drawing's 1'-3", whereas a skinny tub with controls at the same end as the toilet will technically require more than your drawing's 1'-3".)

Answer 2

I hate to answer my own question after putting a bounty but I already posted it as a comment but the correct answer appears to be there is no such clearance requirement.

It appears the whole premise of my question is incorrect unless someone can show that I am wrong. There are clear space requirements for toilets, lavatories, bidets, urinals and shower doors as well as side of lavatory and wall and center to center distances for fixtures. There is no clear space requirement for a bathtub when it comes to standard residential code.

From this 2009 Q&A it says:

Q:Is a minimum 21-inch clearance required in front of a bathtub?

A:No. A minimum 21-inch clearance is required in front of water closets, urinals, bidets and lavatories. Section P2705.1 does not address a minimum clearance around a bathtub. [27-7]

As the current code does not explicitly state what the clear free space should be on the side of the tub I can only assume the above Q&A stands. Provided all other constraints are met, other fixtures should be able to be placed next to a tub at the control end and/or the other end. The current code does not make it as clear as previous versions of the code documents and diagrams did.

It was hard to wrap my head around the fact that there was no clear space requirements next to a bathtub given how other fixtures have such requirements and other websites erroneously state that there is such a requirement.

Answer 3

What everyone has missed is, you need 15" for a total of 30" clear from the center of the water closet(toilet flange) and you need 30" between any sanitary drain. The bathtub drain is 1 sanitary drain. Now on the same wall, as long as the sink sanitary drain is 30" away (center to center). Say you have a 6'2 wall and toilet is farthest left. The flange center needs 15" from wall (drywall not studs) and 15" from any wall, sink, or vanity edge. Say your tub is 30" wide. With a compact toilet with a width of 13". You would only be able to install a 13" wide sink. The left edge of that sink would measure exactly 15" from the center of the toilet. The sink would be installed up against the bathtub. Depending on where you're plumbing sanitary drain center is placed for the 13" sink, you would most definitely be at least 30" away from the bathtub sanitary drain.