Just repeating what I read in an article posted on FR last week. You could probably find it in Search.
I saw the article mentioning the copper, I still wonder about it all, like where the copper starts and ends, that is why I was hoping to get some information from a local contractor.
Around the nation are many “waterless” toilets where the owner simply turned off the leaking supply valve rather than have it repaired, the difference would be that they have no sealed barrier between them and the sewer system.