We are remodeling our bathroom and I want the "old fashioned" two
faucets: one for hot and the other for cold.

Both the plumber and the plumbing supply company say that two faucets
have been declared illegal and that we must, by law, use the one
faucet (for both hot and cold) in the shower. They say that the
legislature mandated one faucet in case someone flushed the toilet and
somebody else is taking a shower.

Only my wife (of 30 years) and I live at home and, duh, we know when
the other is showering or using the toilet. We knock on the wall or
simply ask, "may I flush?"

Yes, I have used the one faucet shower (e.g., hotels) and have a
strong preference for the two faucet shower.

Now, is it really true that some legislature has actually outlawed two
faucets in a shower?

If so, which legistature (e.g., federal, state, county)? I need to
see this in writing.

P.S. I can understand mandating safe electricity practices, of course,
but faucets in a shower?

Thanks.