We're doing a bathroom renovation and I'd like to install a Grohe brand thermostatic valve instead of the "giant circle with a spout" typical in American bathrooms.

grohtherm 2000 rough in

This product has anti-scalding features required by code (you control the temperature by adjusting the lever on the left). The lever on the right is for the diverter.

To install this, we'll rough-in two pipes, a hot and cold. This means that unlike installing a Moen valve, the valve will exist outside the wall.

Product data also has this:

Applicable Codes & Standards:

• Energy Policy Act of 1992

• ASME A112.18.1/CSA B125.1

• ICC/ANSI A117.1

Do you fellas think an inspector will have a problem with this? I'm in WA. Many thanks

  • Have you tried contacting your local building department?
    – Tester101
    Jan 9, 2017 at 18:17
  • 1
    I think it is a terrific idea to have the whole valve accessible, but I see two connections--are these hot and cold into the mixing chamber? Where is the outlet to the shower that the diverter can switch to? Does this valve just slide on over 1/2" copper or other tubing with a Sharkbite type connection? Jan 9, 2017 at 18:25
  • @JimStewart Yes, the rough-in is hot/cold. The shower outlet is on the bottom of the device. Jan 9, 2017 at 18:27
  • @JimStewart Thanks, the valve has the hardware to screw in over the two pipes, like seen here (installation video from manufacturer): youtu.be/Td5-QnZi7lY?t=1m28s Jan 9, 2017 at 18:39
  • 1
    Humm I see that the rough in with tubing only (rather than a roughed in valve body) admits the possibility that the spacing will not be exactly what is required. So these intermediate fittings are required and they allow adjustment of the spacing. This is another threaded joint which can leak, but overall I like the idea of being able to change the whole valve body without having to open up the wall. Is this a long time European arrangement just recently coming to the US? Jan 9, 2017 at 19:22

1 Answer 1


The only way I can see it would be a code issue is that the anti-scald valve is in a unit which could be easily switched out without having to demo the wall. However, I really can't imagine that the code enforcement would limit us all because some very few people would get around the code by installing an expensive valve and then swapping it out after inspection. And presumably all valves on the market which would fit this rough-in do have anti-scald controls.

In my part of the US there is (or was) resistance to mandates on the anti-scald shower valves. So the plumbing inspection procedure had to be changed--they wouldn't issue the final plumbing approval until the wall was tiled. Plumbers were roughing in one valve then replacing it with the older style before the wall was tiled. But one plumber told me that the renegades would then just demo the wall after final inspection and put in non approved valves. Some people are really determined to have their own way.

  • Thanks for sharing! I'll give the City a call tomorrow (looks like it's possible to chat with an inspector early AM) and will update here. Jan 9, 2017 at 20:06
  • One solution to attaching a bar valve youtube.com/watch?v=QO5Ru3kcZI0 Jan 10, 2017 at 19:12
  • I called today and spoke with two different inspectors. They said it should be okay as long as there's one temperature control for the user (no way to scald), and also to hold on to the manufacturer manual for the inspector to review. Seems like it'll be a go! Thanks again for your comments the helpful videos. Jan 11, 2017 at 19:40
  • One more video here youtube.com/watch?v=tP4IzLMwnTI. This shows that the individual offset connection method is supposed to allow adjustment of the spacing, the level and the in-and-out displacement from the wall. To accomplish this the offset connectors must have an effective sealant which allows some twisting adjustment without leaking. The installer here first appears to roughen the threads with a hacksaw blade (!), then winds on fiber, then smears on paste. Whew! I recently had a tense interaction with a German woman. I thought, but did not say: Haben Sie eine Schraube locker? Jan 11, 2017 at 20:14
  • Useful video! Yeah, the connection gives some leeway. Pretty minimal for the Grohe one, but much more for this Toto model: s.yimg.com/xd/api/res/1.2/.pTvHSyqEvP9tJxOtr96zQ--/… Jan 11, 2017 at 20:34

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