Shared Sewage Line for Duplex - Tenant Objects to Charge

[Kirsten M.]

I own a duplex where the sewage lines are shared. A few months ago, I received a call from Unit 1 stating that they were getting backup in their bathtub and bathroom sink. I called a plumbing company and they did a scope and clean out of the lines. The plumber stated that there were roots and about 6ft of "flushable" wipes that were blocking the pipes. Our lease clearly states that only hygienic paper is allowed to be flushed.

I asked tenants from Unit 1 and Unit 2 if they flushed wipes and both parties stated they didn't. *Note*: The plumber stated he observed wipes in Unit 1 next to the toilet. He did not enter Unit 2.

 I will be paying for half the clean out since there was a root obstruction. However, the wipes caused major blockage. The tenant in Unit 2 has moved out I discussed charging her 1/4 the price of the clean out which is $50. She is pushing back and stating that it is unfair that she should have to pay, however, both tenants deny flushing wipes.

What are your thoughts?