My brother in law's house has a mix of ABS and PVC drain pipes and fittings. I don't see any copper or galvanized remnants for drain piping and supplies are all copper as expected. I can't tell if the house was built with ABS drain piping and then remodeled with PVC or vice-versa. I see that they make a PVC-ABS "transition" cement, but like many things in the plumbing aisle, just because they sell it doesn't means it meets code.

I've always used PVC and never paid attention to ABS, in fact they didn't even sell it in NY, but it's common here in the midwest. Is there an application that makes ABS a better choice in certain cases? Why isn't the glue code-compliant, it seems to work OK....I'm guessing you are supposed to use a banded (Fernco) coupling to join ABS and PVC?

Would like to get a little smarter on this subject.

This is the best-informed and most-thoughtful disquisition on this matter I have found: familyhandyman.com/article/can-i-join-abs-to-pvc He reads the code (Minnesota's) carefully and concludes, as you do, that only a Fernco banded sleeve meets code. He also says it doesn't matter in fact because all connections work well. He makes connections of the 3 kinds then breaks them, finds them all strong enough by far. I'm no plumber, so wait for the other guys to answer. I don't know that this guy is right.

When I include the http:// www. before the familyhandyman link, plbg.com censors it. Odd.

I've only had a few occasions to join PVC to ABS, I have always used the glue and never had a problem. That's what got me thinking, what's wrong with the glue? And why do we have 2 types of plastic in the first place?

ABS solvent welds better than PVC and does not need to be primed. ABS can bow and the uv rays from the sun can damage it. ABS will burn and not self extinguish when flame is removed from it. ABS has a different expansion rate than PVC.

I suspect if you have a mix of ABS and PVC in a house then it is originally ABS piped, then later on when ABS was banned they started using PVC to make repairs, resulting in a mix? I know CA banned ABS in 1995 not sure other states.

I found this article (with videos) has some good references on the subject matter.

[structuretech.com]

Sum, ABS is almost exclusively used in CA. Some cities/counties have/had an amendment to the California Plumbing Code, banning all plastic plumbing piping in their jurisdictions.