Is my water lines up to code?

Howdy,

I am having a new home built and the main water line that goes to the water heater is running through and above my furnace.
Can this really be up to code. The builder tells me that it is going through the re-turn air and that there is nothing to worry about and that it is fine. There is also two other spots where the water line goes through the re-turn air heater vent. Just asking about this. Thanks

Through a return air duct is no problem, although I would try to find a different way to run it before doing so.