Are pex water lines required to be insulated when installed in California homes?

I don't live in Cali, but I do fall under the same code (upc). It is not code to insulate pex lines in my area, and I doubt it is in yours. Lets wait and see what Milo has to say about this, as he is a licensed plumber in Cali.

Hello Tonynacha, PEX water line is subject to heat loss just as any other pipe. Yes, in California we have so called T-24 (Title 24 Energy Compliance Code) that mandates insulating hot water pipes. Building Departments are quite strict about complying with T-24.

The wall thickness of the insulation shall be equal to the nominal diameter of the pipe that is being insulated. The Thermal value of such insulation should be rated R-6 or more. As far as type of insulation goes, you can use any type as long as it meets the T-24 R-value requirements.

Hope that helps. Milo

Good to know Milo. Thanks for clearing that up. Just for my own sanity, this is not in the upc, but a local building code, correct?

MGD77: Yes, you are correct in your assumption.