I am installing a whole house humidifier. The manufacturer requires a 1/4" OD copper tubing for the water supply. I would like to use a coil of soft copper tubing from Home depot. It is 1/4" OD and about 0.021 wall C122 copper. Does anyone know if this tubing meets code in Mass? I believe this tubing is called utility grade.

I am planning to cut into a water pipe with a 3/4" to 1/2" tee. Install a 1/2" ball valve ans then use a 1/2" pipe to 1/4: compression to make the connection to the tubing

1/4" O.D. refrigeration tubing is perfect for this application and will meet all MA code requirements!

Purchase a brasscraft 1/2" copper (also called 5/8" O.D.) x 1/4" compression (O.D) straight stop in rough brass for best results (see image)... available everywhere, OK? That should save some time... just be sure to disassemble the valve stem prior to soldering it on!

Mark