Duplex with my Sister-in-Law 16 years ago with no agreement

[Mark Vesu]

All, I bought a duplex with my sis-in-law in 2004 I lived there till 2009. It is a 3BR and 2BR. I own the 3 (59% of built up space) and my SiL owns 2 (41%). From day 1 we paid everything based on this % of ownership, including the downpayment, taxes, landscape maintenance, roof repair, etc.  We never signed anything like tenancy in common. 

She recently bought another SFH and moved to the new place and both units are now rented. I am kind of worried about my liability exposure with something happening on her side of the property. We rent out out units separately, collect the rent and manage it individually. What should I do? Appreciate your advice.