Terrible Sewage back up--how to handle with tenant?

[Jordan Sachs]

Hi all! So I have a tenant living in a single family house. Apparently there is a terrible sewage back up in the basement and it's going to cost $4k to remedy. She never reported it to me or my management company but the smell was so bad that her neighbors finally reported it to the management company and to the city! She hasn't paid her rent yet this month and her lease says she's responsible for sewer issues. I sort of suspect she did't report it since she hadn't paid her rent. She's a nice older lady, definitely low income and I've been super lenient with her about her rent previously but I'm not happy about paying $4k to fix this problem that she clearly let go. Any suggestions on how to handle this? Would you bill it back to her? Evict her? Just eat it? I'm kind of clueless here. I'd hate to charge her $4k but I'm also quite sure if this had been brought to management's attention much earlier we could have avoided this massive clean up. Any advice would be appreciated and thank you in advance!