A plumber friend has told me that the pipe isn't allowed to be plastic because it is exposed to sunlight where it joins to the house and isn't uv resistant. He said that any external pipe exposed to the elements must be metal. Does anyone know where I can find this regulation as we have less than a week till handover of the house and if this is true then I want to be able to bring it up and get it changed

Hi Sarahtas...

In your case, being in Australia, you need to call your local plumbing or building inspector and get the information and specific code from them.

We can't really help from over here in the USA as our codes will be different, OK?

Good luck!

Mark