I am a homeowner in Illinois renovating in a old house (1930s). The renovation is extensive-enough that it requires current code compliance.

We are trying to maintain the historical authenticity of the house (because it was designed by a noted architect) and we are being told that, because of plumbing code, we are REQUIRED to install those ubiquitous, modern, single-handle shower mixers instead of the traditional, separate hot and cold valves.

The regional Kohler showroom (owned and run by Kohler) said they are prohibited from selling individual hot and cold shower valves in the State of Illinois because of code issues.

I am amazed by this.

I see that there are independent temperature compensating valves (tempering valves) available, and independent pressure compensating valves (balancing valves) available.

Can not an arrangement of these valves (located in an adjacent closet wall with a maintenance access panel) substitute for the safety functions of a single-handle shower mixers? After all, what is a single-handled shower mixer but a unified combination of these valves.

I am willing to spend the extra money to engineer an appropriate substitute for the single-handle mixer, but I am being told that nothing will be acceptable.

Is it true that there is no reasonable solution to this code issue?