Looking to get advice from other landlords on a "situation" I've found myself in. I have a portfolio of five duplexes with constant plumbing issues. Some weeks are better than others, but this week alone I've had sewer lines clogged in four different units. There have been feminine products found in the pipes for two of them, but even after removing those the pipes have still been clogged.

One of the plumbers I hired to who used a camera said that the cast iron pipes are old and have scaling and recommended trenchless pipe lining, which (as I understand) is a thin layer on the inside of the pipes that prevent us from having the dig up the pipes and replace them.

I'm wondering if anyone else has come across this technology and has any feedback. It's expensive (5-6k for a duplex), but seems to me to be a much better alternative to replacing the pipes as the duplexes are on a slab and would require jackhammering and other non-fun stuff.

We are going to be sending out notices to tenants to not flush anything outside of toilet paper or pour any grease down the sink. Hopefully that helps, but I still figure the pipes are too old and are going to get worse.

Would love any input.