Late Payment and Additional Fees

[Jovon English]

I inherited a late-paying tenant when I bought a duplex in Ohio a few months ago.  I am an out-of-state investor and managing the property myself, so every time she is late I have to send 3 day notice to vacate via certified mail and regular mail with tracking. 

 It only costs me $15 or so but with this type of tenant, I will have to do this every month until I can finally evict her.  Can I legally tack on this fee to make her pay it since she insists on being late every month?  It is not specifically called out in my lease but obviously I cannot post a notice on the door myself.  And if I have to pay somebody to post the notice, can I charge her that fee?

Also, I believe she is running an unlicensed in-home daycare in my unit.  I can send somebody to go and inspect, but I'm not sure how I can prove this in order to be a violation of the lease.  I already know she will claim landlord retaliation if I send somebody to go take pictures of everything inside.  What are your thoughts?