Tenant withholding necessary repairs

[Chris A.]

I have a tenant (2 adults, 2 children, 1 dog and 1 car). So they have been living in this 3 bedroom 1 bath home for exactly one year. 2 weeks ago the tenant texted me saying they want to renew the lease for another year, so I renewed with a slight increase in rent. As soon as I and renewed the lease the tenant wrote me this long message with all these things wronge, including drain smells bad(she’s been putting bleach down the drain to kill the odor, the lights in the kitchen and bedroom are flickering(this ones easily fixable) & the bathroom floor is in-caving because of water damage(she suggested a new shower door). I feel like they withheld that information when they signed the lease and now Im in this situation where the floor needs to be possibly replaced in their only bathroom while they are living there. I don’t know why the drain pipes smell, the flickering lights are easily fixable, but this bathroom floor situation has me thinking about what I should I do. Any suggestions on how I should approach this?